The first and only French patent I found dates of 1987. Filed by Patrick Huet de Froberville on 15th of June, 1987, and registered on 16th of December, 1988, under the number FR2616574, it depicts a very common nose flute in its functionning and refers explicitly to US2245432, CH253732, US 2197993 and GB214832 patents.
«In this instrument, sound is produced by the vibration of the air contained in a hollow globular body, and produced by the breath of the performer, which breaks on a bevelled edge, characterised in that it comprises a body 2, 3, 4 which is shaped so as to fit the nostrils and mouth of a user and to channel the flow of air exhaled through the nostrils of the latter onto a bevelled edge 8 of an opening 7 positioned in front of the half-open mouth of the user, whose oral cavity 17 is used as a hollow body of adjustable volume. »
« D'une façon avantageuse l'instrument suivant l'invention est réalisé en une matière plastique moulée. »
« L'instrument suivant l'invention est avantageusement réalisé en matière plastique moulée mais peut également être réalisé en métal ou autre. »
So, the nose flute is primarily planned to be made in plastics, but possibly in metal.
The novelty stands in the design of the instrument, not really appealing (to my own taste), with many useless angles, providing a kind of "Darth Vader"/stormtrooper massive look.