He writes that he hopes that Roberts learns from "this unfortunate incident".
Roberts resigned from his executive chairman position today following remarks he made against gender diversity in an interview with Business Insider.
Lévy told staff that the comments were "unacceptable" and "the gravity of his words cannot be tolerated".
The full statement reads:
"You are all aware of the recent incident resulting from statements made by Kevin Roberts that led me to suspend him from his functions, awaiting the final decision of the Supervisory Board.
"Kevin decided to resign from all of his duties as of September 1, 2016, without waiting for the Supervisory Board to meet.
"I am sincerely sorry that Kevin made the unacceptable comments which led him to prematurely end his collaboration with the Groupe. It makes me that much sadder given that we worked very closely and amicably together for 16 years. Kevin also greatly contributed to the Groupe, particularly throughout the early years when he joined the Groupe.
"Unfortunately, the gravity of his words cannot be tolerated, and even less so from a member of the management board. We can only expect that the highest level of our Groupe set the example on our principles and values through irreproachable speech and actions.??
"I wish Kevin the best, and in particular, as he said it himself, to learn from this unfortunate incident."