Fifteen thousand people representing French leftwing organisations marched through the streets of central Paris tonight in protest against American bombing in North Vietnam. No incidents or arrests were reported.

The demonstration caused a massive traffic jam involving thousands of cars packed with homeward-bound office workers for more than an hour.

Police patrolmen and riot squads totalling more than 1,000 men were mobilised for the demonstration and a huge security cordon was thrown around the United States embassy.

The peacefulness of the march contrasted with the last mass protest against U.S. military action in Vietnam last December when baton-wielding police held 300 demonstrators after running street battles.

The march was the last stage of a day of demonstrations during which the organisers had invited people to send messages to President Johnson and the U.S. embassy saying how much the French people condemned the bombing and demanding that it be stopped.