The hosts were thrashed by the French outfit at the Kassam Stadium on Saturday as their European adventure got off to a nightmare start.
"It's on the verge of embarrassment," said Jones. "It was a healthy rugby lesson from a very efficient Stade side. I did not see it coming.
"We have to learn from this lesson and pick ourselves up for the next game in Italy. This is a reality check."
London Welsh have the chance to get their first points on the board when they take on Club I Cavalieri on Saturday.