Investigators reportedly suspect the incident was sparked by a personal dispute and do not suspect it was related to terrorism, Business Insider indicated.
A nearby flat, where a family-of-four were staying, was hit by "shrapnel".
Cops in Avignon, France, are hunting the two suspects who fled shortly after the shooting yesterday.
The attackers are still at large, the newspaper said.
Ever since the Charlie Hebdo terrorist attack in January 2015, French soldiers have been patrolling the streets in Paris and other cities under Operation "Sentinel".
La Provence, citing a source, said two of the injured were taken to hospital and that worshippers leaving the mosque had not been the intended target. Police said the gunmen started shooting, injuring four people at the scene, La Provence newspaper reported.
The prosecutor said."From what we know this evening, the mosque was not targeted".
Police arrested a man in the Paris suburb of Creteil last week after he tried to drive vehicle into a crowd in front of a mosque.
The 43-year-old Armenian raced towards a group of Muslims at high speed in his 4×4.
The prefect of police of Paris has reiterated its instructions of vigilance and the forces of order protecting muslim places of worship.
France remains under a State of Emergency following recent terrorist attacks by Isis and al-Qaeda operatives.