The Paris Observatory (French: Observatoire de Paris) is the foremost astronomical observatory in France.
The construction of the observatory was promoted by Louis XIV of France, a patron of poets as well as scholars. Drawn by Claude Perrault, the plans excluded iron in order to avoid disturbing the compass needles, and wood to prevent the outbreak of a fire. An octagonal southeast tower had 145 steps, while the cellars were placed 27 meters, or 330 steps, underground to maintain the constant temperature required for the proper functioning of the optical and measuring instruments. Beyond the cellars were the catacombs.
The first stone was symbolically laid on the summer solstice in 1667. Five years later, the construction was finished. The director was the Italian astronomer Giovanni Domenico Cassini. This position would be passed on from father to son in the Cassini family until 1791. At that point, the director Jean-Dominique Cassini faced opposition from the National Assembly in regards to his plans for restoring and re-equipping the observatory. After resigning, he was imprisoned.
Upon his release in 1794, Cassini had the Assassin Arno Dorian infiltrate the observatory to recover the former's critical celestial observations. With the research in hand, Cassini was able to retire to the countryside. He would be succeeded as director by Jérôme Lalande, François Arago and Urbain Le Verrier, among others.