After the clubs reached an agreement, Sarr is now discussing personal terms with Bayern ahead of a potential move.
Sarr, 28, has made over 180 appearances for OM, becoming a mainstay in their side over the past five years.
Should the deal be finalised, it will end Bayern’s protracted search for a second right-back.
Sergino Dest was their main target but chose to join Barcelona. And two options from England, Max Aarons and Tariq Lamptey, have proven too expensive for the Bavarians.
Reports in Germany say Michael Cuisance could go the other way to Marseille as part of the Sarr deal.
21-year-old Cuisance was all set for a €20m move to Leeds but failed his medical tests.
The talented midfielder could now return to France where he started out with Nancy.