A fire and building work
In the 19th century, Baron Haussmann literally turned Paris upside down from top to bottom. The city was rebuilt on itself, and it was then that the narrow, dark streets inherited from the Paris of the Middle Ages disappeared. Large, open avenues were laid out and public facilities were distributed. There were plans to bring the police together in a large barracks.
The construction of the Avenue de l'Opéra. Archive images from Wikipedia.
It was all the more urgent because in 1871, during the Paris Commune, the Hôtel de Police, built 50 years earlier under Napoleon 1st, was destroyed by fire. It had to be rebuilt. What was to become the Paris Police Headquarters was built in a rather special location.
A chicken market
The façade of the Préfecture de Police. Photo chosen by monsieurdefrance.com: spech via depositphotos.com
And the place chosen to build the Paris police headquarters was the chicken market. Parisians used to sell poultry there, including (already!) pre-grilled chickens that they could take home to eat. The rebellious humour of the Parisians did the rest and turned the policemen, who passed by in large numbers in the chicken market square, into "poulets" chickens...