The mandatory wearing of face masks while outdoors in many parts of Paris came into effect on Monday, after authorities imposed new measures to curb COVID-19 spread in the French capital.
The order applies to people aged 11 and over in crowded areas, such as along the banks of the River Seine and open-air markets, the BBC quoted the police as saying.
More than 100 streets are covered by the order, according to a list sent out by the police.
However, some popular tourist hotspots, such as the Eiffel Tower, the Arc de Triomphe and the Champs-Elysees, were exempt from the new rules.
Face masks are already compulsory in enclosed public spaces in France.
Violators risk of a fine of 135 euros.
After a strict lockdown, France had flattened the curve of new infections but, since the start of July, cases have been on the rise again.
As of Monday, the country reported a total of 235,237 COVID-19 cases, with 30,327 deaths.