Drought affects the entire country, with 97 departments under prohibition measures and 41 reaching crisis level.
No rain for several weeks and repeated heatwave episodes have led to an unprecedented situation. A quarter of small rivers are dry, according to the latest count released on Monday.
Nouvelle-Aquitaine is particularly affected, with 11 out of 12 departments at the maximum threshold. Vienne has tightened rules to preserve drinking water reserves, including bans on filling private pools and watering lawns and green spaces from 8 a.m.
In the north, the prefect of Manche placed northern Cotentin under restrictions from July 10.
