Built up in 1625 by the architect Salomon de Brosse for Queen Marie de Médicis, the Palais du Luxembourg was the residence for the royal family before it was turned into a prison during
the Revolution.
In 1800, Napoleon Bonaparte ordered renovation works by the architect Chalgrin and in 1804, the first senators were based there. There were 80 of them, forming the "Conservative Senat" which was there to approve the Emperor's decisions. In 1814 the Senat was replaced by the "Chambre des pairs".

A few years later the same question appears again: how will it be possible to house the 271 members of the "Chambre des pairs"?.
In 1836, King Louis Philippe asked the architect Alphonse de Gisors to extend the palace. The building has not changed since. During second World War the palace was occupied, before being freed in 1944. In the year 1958 General de Gaulle set up the 5th Republic and
brought back the Senat that we know today; the 321 senators from the Palais du Luxembourg gather for "commissions" during which they examine written laws; there are 6 "permanent commissions" that are attended by ministers, trade union leaders and many French and foreign experts.

The President of the Senat is the second most important figure after the President of the Republic. His library is made up of some 450 000 books.