London Welsh were handed a rugby lesson on their European debut against Stade Francais in the Amlin Challenge Cup.
Remy Bonfis's try inside three minutes gave Stade the perfect start before Hugo Bonneval and two tries from Waisea Nayacalevu put the visitors in charge.
Gavin Henson's boot and a Greg Bateman score kept the Exiles in touch.
After the break tries from Francis Fainifo, Juan Cruz Guillemain, Felipe Contepomi and second scores by Bonfis and Bonneval rounded off the rout.
Argentina international fly-half Contepomi ended a superb individual display with a 25-point haul.
London Welsh: Davies; Smith, Lewis, Davis, Scott; Henson, Runciman; Montanella, George, Joly; Kulemin, Corker; Mills (capt), Denbee, Jackson.
Replacements: Bateman, Bristow, Ion, Purdy, Williamson, Keats, Whatling, Jewell.