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29 June – Napoleon III installs a huge map of Paris in his office at the Tuileries Palace and he and his new prefect of the Seine, Georges-Eugène Haussmann, begin planning the reconstruction of central Paris.
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21 November – A demonstration of the first tram line between the modern avenue de New York and the Cours-la-Reine. A line is later opened connecting Place de la Concorde with the pont de Sèvres.
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2 April – The newspaper Le Figaro is revived under new management and begins publishing.
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22 February – Private omnibus companies consolidated into the Compagnie générale des omnibus to provide public transport throughout the city.
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26 March – The department store Les Galeries du Louvre opens.
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15 May – The Exposition Universelle (1855) opens between the Seine and the Champs-Élysées. By the time it closes on 15 November, it has attracted five million visitors.
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11 August – Napoleon III decrees the construction of boulevard Saint-Michel and boulevard Saint-Germain on the left bank.
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February 5 to March 31 – Congress of Paris; European leaders meet to bring an end to the Crimean War
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11 October – Inauguration of the train line Paris to Marseille.
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26 April – Opening of the Hippodrome de Lonchamp race track.
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29 June – Napoleon III installs a huge map of Paris in his office at the Tuileries Palace and he and his new prefect of the Seine, Georges-Eugène Haussmann, begin planning the reconstruction of central Paris.
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14 August – Inauguration of the completed Louvre
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29 August – Napoleon III decrees the building of Avenue des Amandiers (now Avenue de la République) and Boulevard Prince-Eugène (now Boulevard Voltaire)
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14 January – Bomb attack on Emperor Napoleon III by Orsini, an Italian nationalist, outside the Paris Opera. The Emperor is unharmed, but 156 persons are killed or injured
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5 April – Inauguration of Boulevard de Sébastopol, the new north-south axis of Napoleon III's urban plan.