French police arrested 11 people on Sunday evening after a clash between youths and leftist activists giving away condoms in front of Notre Dame Cathedral in Paris.

The skirmish broke out after environmentalists and Communist Party activists staged a morning protest on the square in front of the cathedral against recent comments by Pope Benedict XVI over condom use, police said.

About 20 "right-wing" youths shouting "Lay off my pope" clashed with the activists after Mass on Sunday.

The pope drew criticism from some Western governments for saying last week during a flight to Africa that condoms were not the answer to the continent's AIDS epidemic, suggesting that sexual behavior was the issue.