DIEPPE, France — The beaches of Normandy, for most, evoke images of D-Day, the Allied invasion that set the path to victory over Germany.

Fewer people think of Dieppe, this ancient fishing and resort city about a two-and-a-half-hour drive east of those more famous beaches. This is, in part, because the word Dieppe, if it is known at all, evokes something much darker: one of the early and most crushing defeats for Allied forces at a time before the United States had fully mobilized to join them. This is especially true for Canadians, who suffered the heaviest losses here.

But more than 2,000 people — including veterans, their family members, tourists and officials from France, Britain, Canada and the United States — descended on the city for Sunday’s commemoration of the 70th anniversary of the Dieppe raid....