I would go with the Convoi Exceptionnel as Donegal has posted above, it is fairly internationally understood in any language I would think.
Short story, I was on the road west of Dingle one day, 45 seater coach up a few cars ahead of us, got to the pinch point of the road bus couldn’t fit past a line of cars coming opposite direction which were out of sight from where we were. After 10 mins a guy in his 40s came down the road our direction, gesturing and saying we all had to back up, at this stage there were up to 40 cars behind the bus. I somehow thought he was a passenger or the tour guide from the bus. So decided to walk up to see the reason for the blockage. Once I got to the bus there was one driverless car with a wife and 3 kids sitting in it blocking the bus, the other 20 or 30 had backed down to various lay-bys. I offered her to back the car down for her but she refused wit temper. The bus driver in fairness was making the best effort he could to squeeze against the low wall and a few passengers guiding him. Then the guy that had been telling all of us to back up arrived sat in and proceeded to try and pass the bus. Caught the rock face damaging his bumper. I eventually manager to convince him he was not going to fit. So he agreed to reverse. Then the fun started, I have no idea how this guy backed around a corner for his test. At times it looked like he was attempting to do a 3 point turn he was so sideways on the road. I offered to reverse it but he refused. I eventually did the steering in the window. It took 20 mins to get him back 100m to the first lay-by. The bus driver and myself had a good laugh as he passed by. My wife brought our car as the line had extended to 100 cars or so at that stage behind us.
So a sign saying “combine” would mean nothing to a gobs**ti like him.