Please don't try an OHJ in France...if you survive you may well be jailed for endangering life!
At controlled airfields ATC will tell you where to join. At uncontrolled fields you should have been listening out on French unicom of 123.5 to get proper situation awareness before arriving. You then make an all stations call prefixed with the airfield name on the same frequency to let people in the circuit know you are coming. French law requires a downwind join, joining from any other direction is an infringement liable to prosecution. Needless to say an understanding of aviation French is essential.