The Wall Street Journal reports that Pierre Konowaloff has sued the museum in Manhattan federal court on Wednesday. The work is called "Madame Cezanne in the Conservatory."
A collector bequeathed the work to the Met in 1960. The museum said in a statement that it believes it has good title to the painting and will fight the lawsuit.
Konowaloff, who lives in France, filed a similar suit against Yale University last year over a work by Vincent Van Gogh. Yale says it is the rightful owner.
Konowaloff says he is the great-grandson of industrialist and aristocrat Ivan Morozov.