DORTMUND, Germany — He is known here as SS-Siggi, and with his bulky frame and “Germania” tattoos, he certainly looks the part.

For 30 years, which have included several brushes with the law, Siegfried Borchardt — a.k.a. SS-Siggi and who can bear a passing resemblance to Hulk Hogan — has been involved in the far right in this bleak city of 600,000, working from the political fringe. This month, to the horror of the political establishment and many residents, he took his seat on the 94-member City Council.

His ascent has punctured Germany’s image of itself as a country allergic to the nationalism and populism gaining ground elsewhere in Europe. That Germany — in Bavaria, in the southwest, around Frankfurt — is Europe’s economic powerhouse, with low unemployment, booming exports and gleaming stores oozing prosperity.

Dortmund is another Germany: a run-down former coal and steel hub in the industrial Ruhr heartland, with a scruffy north side, few jobs, higher than average crime in some districts, and a large center for registering asylum seekers, and where almost one in three inhabitants are of foreign descent.