Serge Leroy 's sophomore effort for the silver screen (the first one "Ciel Bleu" seems rather interesting but is nowhere to be found)has a strong male cast :Michel Constantin,was par excellence,the tough guy of the French B movies (but in his filmography one masterpiece :Jacques Becker's "Le Trou" (1959),the best French prison movie ever made ,and no ,it's not a Nouvelle Vague work!);Georges Géret ,Pierre Santini and Adolfo -"Thunderball"-Celi provide good support;unfortunately ,Cathy Rosier is as expressive as a Barbie doll and Annie Cordy's role is underwritten.The story is complicated instead of complex :it involves secret microfilms ,frame-ups,corrupt lawyer and lots of dollars ,plus a song by Annie Cordy .But all in all ,it's just another thriller .Leroy's next movie "La Traque" will be simpler and much more absorbing .The title: it's explained in the movie ;a "Mataf" is slang for "sailor" who joins the navy for five years ;the connection with the movie is thin,unless the hero's ship (in the last sequence) counts