Sadly,smoking is still going on among PAX, even on the US-registered airlines. Last summer coming back from Paris to SFO on UA, we were seated in the exit row seats ( lots of leg room but the lavaratories are way too close). The crew, although all United employees, were native French and were based in Paris. The plane had mostly French PAX flying to some convention to the US. If you've ever been to Paris, you should know that smoking for the French is almost a national passtime. EVERYBODY smokes and a LOT. So you can imagine what a tourture the 12-hour flight might have been for them. Sitting by the lavs, we could tell(smell) clearly that there was a lot of smoking going on during the flight. Amazingly, the FA's on the flight chose to ignore it ( comradery and mutual understanding among fellow coutryman?). I have no idea why the alarms did not alert the pilots. Maybe they were French too (the pilots). In hindsight, we should have spoken up about the fresh smell of sigarette smoke coming from the lav everytime the door got open. But what's the point? The FA were smelling it too and were doing nothing! US natives were a clear minority on this flight and I did not want to start a coup and to be thown off the plane by the irrate smokers. Well,may be next time I'll have more guts to speak up or to write United management about what's going on on their planes.