NICE, FRANCE -- At least 20 artworks worth millions of dollars, including paintings by Picasso, Renoir and Degas, were stolen by thieves who lowered themselves into a fifth-floor apartment by rope, police said Thursday.

Police said there was no burglar alarm system in the studio apartment in Cannes, owned by a former government official and used by his son, who works as a night watchman.

The son, Armand Schwarz-Fuchs, discovered the theft when he returned from work early Wednesday, police said.

Among the works reported stolen were paintings and engravings by 19th- and 20th-century masters Pablo Picasso, Pierre-Auguste Renoir, Edgar Degas, Amedeo Modigliani and Edouard Manet.

Officials initially estimated the value of the stolen works at nearly $2 million, but police said Thursday that the value was likely to be much higher. The French news agency Agence France-Presse quoted one source as saying the total value could be $190 million.

French press reports suggested there was uncertainty as to the origin of the works, and police said they wanted to talk to the apartment's owner, Jacques Schwarz-Fuchs, 62.

A retired member of the Council of State, Schwarz-Fuchs reportedly is ill and receiving medical care in the eastern city of Strasbourg.

According to police, the thieves broke through a balcony window of the apartment after lowering themselves by rope from the roof, two floors above.

Several major thefts of privately owned artworks have occurred in the past two years in Cannes and nearby Nice.

In December, eight oil paintings by Henri Matisse, valued at more than $12 million, were stolen from a Nice apartment. The works were recovered in January, and a suspect was tried and sentenced to three years in prison.