An Art Deco small silver gilt rectangular box

An Art Deco small silver gilt rectangular box, decorated overall with black enamel, mounted with a circular lapis lazuli section centred with a small ruby, French control marks to the gold collet mount, further French control marks to the interior, stamped twice with inventory number S2923, the interior hinged cover depicting a musical score with treble clef and acrostic musical notes BDCA, 3.2cm wide