The 31-year-old will add much-needed depth to the Wolves back-line, as the Brazilian can cover at both left-wing-back and left of a back three.
Despite his extensive top tier experience – having helped Lyon to the Champions League semi-final last season – Marcal has joined Nuno's side for a fee understood to be around £1.8m.
He has signed a two-year deal at Molineux.
Executive chairman Jeff Shi said: "We are very pleased Marçal has joined the pack.
"Having played over 280 games in top leagues, as well as Champions League football, Marçal will add a huge amount of experience to our young team.
"He is a player with the technical ability to be able to contribute in the build up play from the back, all the way through to threatening the opposition in the final phase.
"He possesses good pace and has a great work ethic, to work up and down the football pitch. Defensively he is very solid and will add to our group with his ability in the air as well.
"Of course, because of his nationality, Marçal was subject to a work permit application, and I am delighted that the panel shared our view on the player’s quality and how he can help Wolves.
"Welcome to Wolves Marçal, you are now part of our pack!"
The signing comes just over 24 hours since Wolves smashed their club record fee, signing 18-year-old striker Fabio Silva for £35m.