Artiste model. Based on my research it appears likely manufactured in Paris in the 1940s or 1950s.
Vintage Clarinet M.Masson by Thibouville Freres IVRY (EURE) Made in France
Clarinet M.Masson by Thibouville Freres IVRY (EVRE) ECOLE #5030 Made in France
THIBOUVILLE FRERES WOOD CLARINET M MASSON PARIS FRANCE HARMONIE
VINTAGE THIBOUVILLE FRERES M MASON PARIS FRANCE WOOD CLARINET 1930S
Martin Freres LaMonte Paris Grenadilla Wood Clarinet #2 in the Blue velvet cased