"Several tonnes of cannabis have been recovered and they account for about €40 million," Valls told reporters, referring to busts last week that saw 17 parallel arrests with a deputy mayor of a Paris district, Florence Lamblin of the Green Party, among those charged in the case.
Valls said the laundering scheme was "linked to the drug smuggling racket and was easily estimated at €100 million (121 million francs $129 million)."
The main Swiss suspect in the case has been arrested and his brother, a wealth manager with the HSBC Geneva bank, has also been detained.
A raid on the Geneva home of one of the brothers led to the discovery of €800,000 in cash, and 160 watches and jewels worth an estimated €2 million in a hidden safe, Swiss newspaper Le Temps had reported.
The main suspect's lawyer Stickel-Circurel told Le Temps Monday that her client had knowingly helped tax evaders, "but he had no idea where the money came from."
A third person, a woman working for the main suspect, was also arrested along with the two brothers last Wednesday. She has been set free but must remain available for questioning.
Those arrested and released were freed on bail of between €80,000 and €1 million, a judiciary source said.
A source close to the case said police had found several million euros in cash and goods during the searches of suspects homes and safe deposit in both countries.