Nine suspects were arrested as part of counterterror raids by French police near the greater Paris region and the Alpes-Maritimes department on the south coast, according to local media on Tuesday.
An arrest was also made in Switzerland, bringing the total number of suspects held to 10, according to French broadcaster BFMTV quoting sources close to the investigation.
The arrested individuals -- aged between 18 and 60 -- are suspected of planning and preparing a terror attack.
Police identified them after intercepting "disturbing remarks" exchanged between the suspects on the Telegram encrypted messaging application.
France is on high alert since the November 2015 terrorist attacks across Paris which left over 100 people dead.
It has remained the target of several deadly terror attacks during these two years, despite a state of emergency extended several times.
French Interior Minister Gerard Collomb said last week at least 32 planned attacks had been foiled over the last two years "thanks to information from abroad or through specific measures related to the state of emergency".
The state of emergency ended on Nov.1 and was replaced by a new anti-terror legislation, widely criticized by rights groups.
