The restaurant, located on the heights of Mougins, belongs to a private individual. The perpetrators entered through a French window and took the six engravings in less than a minute.
The engravings have been returned. They will now be kept in a secret location.
Investigations continue in order to establish the exact role of each person and the possible existence of a mastermind.
The authorities have not disclosed the name of the restaurant or that of the owner.
No information has been given about any possible arrests beyond the identification of the suspects.
The facts illustrate the vulnerability of collections displayed in places open to the public, even when they are protected.
Mougins, a municipality in the Alpes-Maritimes, is known for its artistic heritage and its gastronomic establishments.
The theft dated back about a month. The pieces, of great value, had not been damaged.
The works, untraceable since the theft, were hidden in a hideout.
Thanks to video surveillance, investigators identified the perpetrators as well as their alleged accomplices. According to them, the theft may have been committed on commission.