PARIS (Reuters) — A ban on street prayer came into force on Friday, driving thousands of Muslim worshipers in northern Paris into an improvised prayer site in an old fire brigade barracks, angering a small but vocal minority.

The prayer ban has highlighted France’s difficulties in assimilating many of its five million Muslims, who often lack spaces to pray, and it follows a long-smoldering dispute fanned by the far-right leader Marine Le Pen.

The Interior Ministry under Claude Guéant has directed Paris’s Muslims to temporary spaces made available pending the construction of a new space and warned that force would be used if necessary as the police enforce the ban.

Seven months before a presidential election, the ban has struck some in France as an attempt to rally the far right to President Nicolas Sarkozy’s center-right camp.