The couple wed during a traditional Jewish ceremony in Paris last Monday in front of a few close relatives, the magazine reports.
"We did it — we're married!" Fisher, 34, wrote in an email to friends the next day, according to Woman's Day. "I thought of you as everything was happening, but Sacha and I wanted no fuss — just us!"
The Australian actress and Baron Cohen, 38, got engaged in 2004 and have a 2-year-old daughter named Olive.
Emails to Fisher and Cohen's reps were not immediately returned.