Jules René Hervé (French 1887 - 1981)

Jules René Hervé was known for his landscape oils. I recently purchased an unsigned watercolor landscape/seascape, with no information under the dust cover, but with a label on the dust cover containing Hervé's name, hand-printed, apparently indicating that a prior owner attributed the work to Hervé. Does anyone know: 1. whether Hervé ever painted with watercolors, 2. whether he ever failed to sign his work, 3. the name of a gallery with which he dealt, 4. the name of an expert who might be able to identify his work?