The Soleau envelope, named after its French inventor, is a sealed envelope serving as proof of anteriority for inventions valid in France, exclusively to precisely ascertain the date of either an invention, idea or creation of a work. It can be applied for at the French National Industrial Property Institute (INPI). The working principles were defined in the ruling of May 9, 1986, published in the Official gazette of June 6, 1986 (Journal Officiel de la République Française or JORF), although the institution of the "Soleau envelope" dates back to 1915.
The envelope is made up of two compartments which must, each, include the very same version of the element for which registration is sought. The INPI laser-marks some parts of the envelope for the sake of delivery date authentication and sends one of the compartments back to the original depositary who submitted the envelope.
The originators must keep their part of the envelope sealed; it should only be unsealed in case of litigation. The deposit procedure can be either made at the INPI, by airmail or in the INPI's regional subsidiaries. The envelope is kept for a period of five years, and the term can be renewed once.
Note: the envelope may not contain any hard element such as cardboard, rubber, floppy disk, leather, staple or pin. Moreover each compartment can only include up to 7 A4-size paper sheets, with a maximum of 5 millimetres (0.2 in) thickness. If the envelope is deemed inadmissible, it is sent back to the depositary at his own costs.
Also, unlike a patent or utility model, the depository has no exclusivity right over the deposed element. The Soleau envelope, as compared to a later patent, only allows use of the technique, rather than ownership, and multiple people might submit envelopes to support separate similar use, before a patent was granted to restrict later uses.
In case of an invention, the envelope only constitutes proof that the depository knew the invention before any patent application at the INPI or at the European Patent Office for the French territory, and allows him to continue exploiting the invention. Personal exploitation is practically very restrictive and can't be licensed in either manner to third parties. It is only valid for French jurisdiction and intends to assert a date of creation, not to protect an invention, idea or work.
- Stephen Pericles Ladas, "Patents, trademarks, and related rights: national and international protection", Volume 3, Harvard University Press, 1975, p. 864, referring, in footnote 118 to: "On the French law and the institution of the Soleau envelope, see Prop. Ind. (1915), pp. 103 ff.
- (French) INPI web site, User's guide to the enveloppe Soleau
- (French) INPI web site, The life of an enveloppe Soleau