PARIS, April 2 (JTA) — Far-right leader Jean-Marie Le Pen has called on the extreme-right movements of Europe to join forces. “We propose in the coming days a form of political cooperation between our countries. Why not call this `Euro-Nat’ — a grouping of the Europe of nationalists, of the Europe of nationals,” the anti-immigrant leader this week told a party congress in Strasbourg. The congress was held while an estimated 40,000 people marched through the streets of Strasbourg to protest his National Front party, which advocates expelling France’s 3 million mostly North African immigrants, reserving jobs and welfare for French nationals and taxing companies that employ immigrant workers. The congress was called to elect party leaders, draft a legislative platform and plan strategy for parliamentary elections in 1998. But it was upstaged by the mass number of protesters, which included Jewish, left-wing and anti-racist groups. Strasbourg’s Socialist mayor, Catherine Trautmann, also took part in the demonstration. It was believed to be the biggest anti-Front protest ever, and the largest in the city since the end of World War II. Members of France’s conservative ruling coalition stayed away from the mass demonstration, but they showed their opposition to the National Front by laying a wreath at the site of a synagogue the Nazis burnt down during the war. Le Pen, who denies he is racist or anti-Semitic though he has made anti-Jewish remarks in the past, said his sympathizers were being treated as outsiders. He said the protesters were treating his followers as though they were “a caste of less-than-citizens, pariahs who remind us of plague victims during the Middle Ages or the Jews of Nazi Germany.” Several other European extreme rightists spoke at the congress, including Ricardo Saenz de Ynestrillas, head of Spain’s National Unity Alliance, and Frank Vanhecke, president of Belgium’s Flemish Bloc. The National Front recently won control of a fourth southern town in municipal elections, but it has no seats in Parliament. In some of the towns the party controls, city officials have ordered school cafeterias to stop serving special meals for Jewish and Muslim children. The Alsace region in which Strasbourg is located gave Le Pen an exceptionally strong show of support in the 1995 presidential elections. The region has one of the lowest immigrant populations in the country. One of every four people in the region, which borders on Germany, voted for Le Pen in 1995, compared with 15 percent nationwide.