City hall has issued a decree banning indecent clothing to preserve the tranquility of the sandy beaches created on the banks of the River Seine every summer since 2001.

"People must behave according to good standards to maintain tranquility, security and public order," the decree said, according to Saturday's edition of Le Parisien. "Notably indecent attire (nude sunbathing, g-strings and toplessness etc) is forbidden."

The city police will be enforcing the rules, and anyone caught baring too much flesh risks a 38 euro ($48) fine.

Defending the decree, city hall sports official Pascal Cherki told Le Parisien that indecent clothing "could have led to temptations and dangerous behavior on the banks of the river."

Topless sunbathing and g-strings are common on real beaches around France in the summer.