Paris ? The long-flailing French left made a big-time comeback Sunday, crushing Nicolas Sarkozy’s conservatives in regional elections colored by voters’ economic worries — and informally kicking off the 2012 presidential race.

Cheers resounded from Socialist Party headquarters as leftists swept races from the French Riviera to Paris. With 97 percent of ballots counted, the Socialists and their allies won 54 percent of the vote nationwide, while Sarkozy’s UMP party had 35.3 percent, according to the Interior Ministry.

The results show what a rough road the dynamic but increasingly isolated Sarkozy has ahead of him between now and 2012. Nationwide strikes are planned Tuesday by some of those who punished his party Sunday: train drivers angry over pension reforms that are a pillar of his presidential policy, and teachers angry over job cuts. Meanwhile, he faces new challenges from a popular green movement and a reinvigorated extreme right.