Method for controlling the opening speed of a valve connected between a fuel tank and a filter, and configured to relieve the pressure inside the fuel tank into the filter, the method comprising the steps of:— Measuring a pressure in the fuel tank,— Measuring or inferring a fuel vapor temperature in the fuel tank,— Calculating an opening speed as a function of the pressure and the fuel vapor temperature in the fuel tank,— Opening the valve at the calculated opening speed in order to avoid corking of another valve of the fuel tank connected between the valve and the fuel tank. Assembly for putting the method into practice