The backing for the vaccine, the fourth to be authorised in France, comes after approvals by the European Union and the World Health Organization.
It has also received the green light from regulators in the United States, Canada and South Africa.
The single-shot jab should be used preferably in areas where the epidemic is “particularly active”, the French HAS agency said.
It recommended the vaccine could be used for all adults, including people over 65 and those at risk from severe forms of Covid.
Clinical trials have found the J&J shot to be 67 percent effective against all forms of Covid-19, a number rising to 85.4 percent for its effectiveness in preventing severe disease.