The 30-year-old "Girls" creator has lend her support behind those suggesting people to rip any posters they see of the film, reported Huffington Post.
The poster for the fifth installment in 'Bourne' franchise features "The Martian" star posing with a gun.
Dunham re-posted a picture from television producer Tami Sagher's Instagram account, in which Damon's gun-bearing picture has been peeled away.
"Hey New Yorkers, what if we do some peeling and get rid of the guns in the Jason Bourne subway ads. So tired of guns," Sagher wrote while sharing the photo.
This comes after two black men - Alton Sterling and Philando Castile- were shot dead by cops, which led to the subsequent deaths of five officers in a shooting during the Black Lives Matter protest in Dallas.