The city of Paris is suing Airbnb for €12.5m (£11m) over 1,000 adverts for what it says are illegal rentals.
Homeowners in the city can rent out their properties for only 120 days per year. They must register themselves as a business and display their registration number on any advertising.
Under French law, companies can be fined up to €12,500 for each advert.
Airbnb said the rules in Paris were “inefficient, disproportionate and in contravention of European rules”.