French actress Mathilde Warnier, after Valentino, Paris, September 2016.
A chic (very French!) way to dress down a beautiful cocktail dress — add a camo/utility jacket or shirt. 
Recreate Mathilde's look (kind of):
Valentino camouflage-print jacket, Vis A Vis Cotton-blend hooded jacket, Topshop Camouflage shacket, J.Crew Camouflage utility shirt-jacket, MiH Jeans x Golborne Tiger Camo cotton jacket, Harvey Faircloth Patch camouflage cotton field jacket, L'Agence Camo Print military jacket, or Ax Paris Camo jacket
Valentino Fit and Flare cocktail dress