Industrial action by French seamen blocked the port of Calais yet again on Sunday, stranding hundreds of passengers waiting to board ferries for England.
About 15 sailors from the bankrupt firm Scop SeaFrance took to the water in two lifeboats, a source at the port said.
"Traffic is totally blocked, as a safety measure, as lifeboats are in the port," the harbour master in Calais.
Hundreds of passengers were unable to board ferries for Britain as a result.
Scop SeaFrance workers have been protesting plans to sell off some of their ferries to rival Danish firm DFDS, a move expected to result in hundreds of job losses.
The latest action by the seamen from comes on the eve of a key meeting on a deal to resolve the dispute, which would see up to 407 of the 487 sailors keep their jobs.
Calais has also lately been the scene of a nightly cat-and-mouse game between police and hundreds of migrants trying to get into Britain via the undersea Channel Tunnel that links the two countries.
On Monday, Prime Minister Manuel Valls is to travel to Calais along with two EU commissioners to discuss the migrants issue.
In July, striking ferry workers blocked Calais for three consecutive days, causing havoc with cross-Channel sailings and huge tailbacks on roads in the region.
The action earlier in the month also sparked cancellations on the Eurostar passenger train service between France and Britain.
The ferry route from Dover in England to Calais is one of the busiest in Europe, with British holidaymakers using it to get to the Continent by car.