RNA - According to a PressTV report, One of the grenades in the Thursday attack exploded, but no injuries were reported.
According to local press reports, police discovered three unexploded grenades used in the attack and cordoned off the mosque.
The assault in the city came a day after the office of the French satirical weekly, Charlie Hebdo, in the capital, Paris, came under a shooting attack.
The shooting left 10 staff members of the magazine as well as two police officers dead.
Additionally, the mosque in Le Mans was targeted with gunfire overnight, with one bullet striking the place of worship.
Police in France have reported several other assaults against mosques across the country since Wednesday.
Earlier on Thursday, an explosion was reported at a small Middle Eastern restaurant near a mosque in Villefranche-sur-Saone, eastern France.
There were, however, no reports of injuries as a result of the blast and the source of the explosion remains unknown.
French authorities have enforced a high state of alert in the country.
Prime Minister Manuel Valls of France was cited as saying that extra security forces have been deployed to secure mosques, synagogues, department stores, shopping centers, train stations and airports.
R111/108/C/