"The Avengers" star secretly married the French journalist in Philipsburg, Mont., on Oct. 1, according to People, which cited a clerk for Montana's Granite County.
Reps for the ultra-private star did not immediately respond to a request for comment.
The 30-year-old beauty started dating Dauriac in 2012, and they got engaged in late 2013. The comely couple welcomed their first child, daughter Rose, in September and asked for privacy for their family.
The "Lucy" star made her first post-baby red carpet appearance with twin brother Hunter Johansson on Nov. 18 at the Friends of Rockaway 2nd
It's the second marriage for Johansson, who was wed to actor
Page Six was first to report news of the marriage.