根據維基百科條目 International Klein Blue,他沒有為該發明申請專利,只是向法國相關部門登記了發明日期:
In May 1960, Klein deposited a Soleau envelope, [3] registering the paint formula under the name International Klein Blue (IKB) at the Institut national de la propriété industrielle (INPI). Contrary to popular belief, Klein never patented IKB. Only valid under French law, a soleau enveloppe merely registers the date of invention, according to the depositor, prior to any legal patent application. The copy held by the INPI was destroyed in 1965. Klein"s own copy, which the INPI returned to him duly stamped is still extant. [4]