From the Wikipedia page  which contains references.
Legal deposit is a legal requirement that a person or group submit copies of their publications to a repository, usually a library. The requirement is mostly limited to books and periodicals. The number of copies varies and can range from one to 19 (in Poland). Typically, the national library is one of the repositories of these copies. In some countries there is also a legal deposit requirement placed on the government, and it is required to send copies of documents to publicly accessible libraries.
In the year 2000, UNESCO published recommendations for the construction of legal deposit legislation
Legal deposit by countryEdit
In Australia, section 201 of Copyright Act 1968 and other state Acts requires that a copy of every book published in Australia be deposited with the National Library of Australia. State laws require books published in each state to be deposited in the applicable State Library. New South Wales, Queensland and South Australia require books published in those states to be deposited in the library of the state Parliament. New South Wales law also requires books published in that state to be deposited in the University of Sydney Library.
Legal deposit legislation in Brazil ("Depósito legal"), federal laws number 10994 as of December 14, 2004. The Brazilian legal deposit Act requires that one copy ] of every book, music or periodical published in the country be sent to the National Library of Brazil (known as Biblioteca Nacional, Biblioteca do Rio de Janeiro, or Fundação Biblioteca Nacional), located in the city of Rio de Janeiro.
In Canada, the Library and Archives of Canada Act (2004) specifies that up to two copies of any published material must be deposited with Library and Archives Canada. Materials deposited in the archives are catalogued; the catalogs are available as part of the Library and Archives Canada website.
In Denmark, legal deposit has been required since 1697, and is handled by the Royal Danish Library (for most written works) and by the State and University Library (for newspapers, audio, and video); two copies must be supplied. This also includes works in digital format, and the publisher may be required to supply the necessary passwords.
In Finland, The Royal Academy of Turku was given right to receive a copy of all works published in Sweden in 1707. After Finland had been ceded by Sweden to Russia, this privilege was confirmed in 1809. In 1820, all Russian print presses began to send legal deposit copies to Finland.
Gaining its independence in 1917, Finland retained the principles of legal deposit. Helsinki University Library (the university had been transferred from Turku in 1827) remained the main deposit library. Additional copies began to be deposited in other libraries in Turku, Jyväskylä, and Viipuri (later Oulu). In 1984, the obligation to deposit was expanded to audiovisual materials; responsibility to preserve films was given to the National Audiovisual Archive.
A new act on depositing and preservation of cultural materials was given in 2007. The new act covers two new important types of cultural materials. The National Audiovisual Archive collects and preserves broadcast materials, whereas the National Library of Finland (Helsinki University Library renamed) takes care of capturing and preserving Web contents.
In France, legal deposit was initiated by the Ordonnance de Montpellier of 1537, under which a copy of any published book had to be delivered to the king's library, for conservation purposes. During the following centuries, legal deposit was sometimes used to facilitate censorship and the obligation was thus removed briefly during the French Revolution], under the argument that it violated freedom of speech. The main depository is the Bibliothèque nationale de France. Legal deposit is extremely developed and concerns not only printed material but also multimedia archives and even some web pages.
The French Wikipedia page on legal deposit in France is 
In Germany, the law about the German National Library (Law about the German National Library) requires that two copies of every printed media and some nonprinted media be sent to the German National Museum in either Frankfurt am Main or Leipzig (depending on the publishers location). Additionally, each State of Germany] requires one or two copies to be sent to their respective legel deposit (usually state university libraries).
In Iceland, four copies of any published, printed, material must be sent to the National and University Library of Iceland, three of which will be kept there, and one of which will be kept at the Municipal Library of Akureyri. If fewer than 50 copies are made only two are required.
The Delivery of Books Act 1954 enacted by the Indian parliament regulates the deposit of books published in India to the National Library of India, Kolkata and three other libraries namely, Connemara Public Library, Chennai; Central Library, Mumbai and the Delhi Public Library. The Act was amended in 1956 to include periodicals and newspapers. The Indian National Bibliography is complied on the receipt of books received under Delivery of Books Act at the National Library, Kolkata.
In the Republic of Ireland, the Copyright and Related Rights Act 2000 specifies that one copy of every book published is to be delivered to the National Library of Ireland, Library of Trinity College, Dublin, the library of the University of Limerick, the library of Dublin City University, and the British Library. Four copies are to be delivered to the National University of Ireland for distribution to its four constituent universities. Further, on demand in writing within twelve months of publication a copy is to be delivered to the Bodleian Library, Cambridge University Library, the National Library of Scotland and the National Library of Wales.
In Israel, "The Books Law 2000 (5761)" requires two copies of each publication to be sent to the National Library of Israel. At their request, the library of the Knesset and the Israel State Archives are entitled to receive one copy each.
The government authorities are required by the "Freedom of Information Act, 1999" to send an annual report of their actions to the public library of every town with 5,000 people or more.
In Italy, the law on legal deposit requires a copy of each publication to be sent to both the National Central Library of Florence and National Central Library of Rome, as it has been since the institution of the Kingdom of Italy (1861.
In addition, the regions determine local regional and provincial legal deposit libraries, which receive two more copies and often inherit that status from their pre-unification history. For instance, the Biblioteca Nazionale Braidense is the Lombardy legal deposit library since 1788 (when it covered the Duchy of Milan), and the National Central Library of Florence since 1743 (for the Grand Duchy of Tuscany).
In Monaco four copies of locally produced books, computer software and media must be deposited in the Bibliothèque Louis Notari. If fewer than 100 copies were produced only two copies are required.
The legal deposit was initiated in 1903 in New Zealand, and requires that copies of all printed documents, offline documents (e.g. DVDs), internet publications and websites are sent to the National Library of New Zealand within 20 working days of publication. This process is given legal force by Part 4 of the National Library of New Zealand (Te Puna Mātauranga o Aotearoa) Act 2003. If more than 100 copies are printed in total, 2 copies must be provided, otherwise 1. If the price of 1 copy is greater than $1,000 NZD, only 1 copy is required.
Since 1780 the Republican Library has been entitled to a copy of all works published in Poland. In modern times the issue is regulated by a Decree of the Minister of Culture and Arts of March 6, 1997. The National Library of Poland and the Jagiellonian Library receive two copies of all publications, one of which is to be stored indefinitely. In addition to that, there are 15 other libraries to receive legal deposits to be stored for no less than 50 years: Maria Curie-Skłodowska University Library, University of Łódź Library, Nicolaus Copernicus University Library, Adam Mickiewicz University Library, Warsaw University Library, University of Wrocław Library, Silesian Library, City of Warsaw Library, Pomeranian Library in Szczecin, University of Gdańsk Library, Catholic University of Lublin Library, University of Opole Library and Podlaskie Library in Białystok. The National Film Library (Filmoteka Narodowa) is to receive all film productions, while the Sejm Library receives a copy of all legal documents.
In Portugal, all publishers are currently required to deposit 11 copies of all publications, which are distributed between the National Library of Portugal, municipal libraries of major cities, and the libraries of public institutions of science and higher learning. Special exceptions, of which only one copy is required (and stored in the National Library, include Masters and PhD dissertations, limited prints, stamps, plans, posters, among others.
In Russia the Russian State Library (Moscow), the National Library of Russia (St Petersburg), the Library of the Russian Academy of Sciences (St Petersburg), as well as the libraries of the Moscow State University, the President of the Russian Federation, and the two Houses of the Federal Assembly of the Russian Federation are entitled to a copy of every book published.
In Singapore, the National Library Board Act requires all publishers in Singapore to deposit two copies of every publication to the National Library Board at their own expense within four weeks from the publication date.
The forerunner of the National and University Library of Slovenia, the Lyceum Library of Ljubljana was established around 1774 by a decree issued by Maria Theresa from the remains of the Jesuit Library and several monastery libraries. The submission of legal deposit copies to the Lyceum library became mandatory with a decree published by the Austrian court in 1807, at first only in Carniola, except for a short period of French occupation, when it received copies from all the Illyrian provinces. In 1919, it was named State Reference Library and started to collect legal deposit copies from the Slovenia of the time. In the same year, the University of Ljubljana (the first Slovenian university) was established and the library served its needs too. In 1921, it started to acquire legal deposit copies from the entire Kingdom of Yugoslavia. It was named the University Library in 1938.
In South Africa the Legal Deposit Act, 1997 requires publishers to provide five copies of every book published, if the print run consists of 100 or more copies. These copies must be deposited in the National Library of South Africa (NLSA) in Cape Town, the NLSA in Pretoria, the Mangaung Local Municipality Library Services in Bloemfontein, the Msunduzi Local Municipality Municipal Library in Pietermaritzburg, and the Library of Parliament of South Africa in Cape Town. If the print run is less than 100 copies, then only one copy is required, to be deposited in the NLSA in Cape Town. If it is less than 20 copies, then no deposit is required.
For films, videos and sound recordings, the requirements are the same, except that the National Film, Video and Sound Archives (NFVSA) receives a deposit copy instead of the Library of Parliament, and if only one copy is required it is deposited in the NFVSA rather than the NLSA.
In Spain, the obligation to deposit copies of printed materials has existed since 1619 for the Royal Library of El Escorial and since 1716 for the Royal Library of Madrid (later the National Library of Spain). From this moment, there followed multiple provisions, in the 19th century termed "legal deposit", all with the aim of enforcing compliance.
The decree of 1957 established a solid administrative base for legal deposit in Spain, based on the separation between provincial offices that managed legal deposit at the local level and conservation libraries, such as the National Library. The decree stipulated that printers were responsible for depositing several copies of all published works at the National Library and other public libraries. This legal deposit legislation covered a wide range of materials, including printed materials such as books and magazines, sound recordings, maps, movies, and postcards.
The 1957 decree, though superseded by other decrees in 1971 and 1973, remained almost intact until 2011, when a new legal deposit law was passed on July 29, 2011. Law 23/2011 established, among other things, that the publisher, not the printer, was the primary entity responsible for submitting its materials to legal deposit. It also established procedures for the legal deposit of electronic materials, including online ones. The number of copies that must be delivered to each library varies between two and four according to the type of material. Through legal deposit, the National Library collects all materials published in Spain. The central libraries for each autonomous community, and provincial libraries collect works published in their respective provinces.
In the United Kingdom the Legal Deposit Libraries Act 2003, applies to the United Kingdom. restates Section 15 of the Copyright Act 1911, that one copy of every book (which includes pamphlets, magazines and newspapers) published there must be sent to the British Library; five other libraries (the Bodleian Library at the University of Oxford, Cambridge University Library, the National Library of Scotland, the Library of Trinity College, Dublin and the National Library of Wales) are entitled to request a free copy within one year of publication.
In the United States, any copyrighted work that is published must be submitted in two copies to the United States Copyright Office at the Library of Congress. This mandatory deposit is not required to possess copyright of unpublished works, but a copyright registration can give an author enhanced remedies in case of a copyright violation.