France, July 4 -- Many delegates arrived at the conference venue before protesters set up blockades, allowing this weekend's two-day meeting to begin on time.

Police said around 31,000 people took part in largely peaceful demonstrations, while organisers put the figure at more than 50,000.

Protesters blocked roads into the city, with some abseiling from a motorway bridge, while others staged sit-in protests that disrupted bus and tram services.

"It's important to send a signal against the shift to the right," said 19-year-old demonstrator Lene Krug. "The AfD is an anti-democratic party that spreads hate." State elections

The AfD, which has topped recent national opinion polls, is hoping to make further gains in state elections in east...