France, March 13 -- The issue has forced a political rethink at Brest's city hall. Socialist Francois Cuillandre, the city's mayor since 2001, has reversed his long-held opposition to creating a municipal police force and now says he will do so if re-elected.

Nowhere is the impact of the drug trade more visible than in the district of Bellevue, 15 minutes from the city centre by the newly installed tram line. On a grey afternoon, the area looks calm enough. Children gather at the ice rink. A bakery, creperie, kebab shop, butcher, pharmacy and grocery store line the street near Place Napoleon III.

"In itself, it's not bad here," says Ophelie, who moved to the neighbourhood three years ago.

But Bellevue has become symbolic of Brest'...