"integer" as used here is simply another word for an element or feature. I am not aware of any more specialised term in French, but if you use "élément" you will at least not be wrong.

Take a look at the following links in combination:

Integer (ALL): A distinct feature or element of a claim.
http://www.piperpat.com/IPInformation/IPGlossary/tabid/63/De...

In France, the scope of protection afforded by the patent is reasonably broad and replacement of a specified integer of a claim by an equivalent will not normally result in avoidance of infringement.
http://www.ladas.com/Litigation/ForeignPatentLitigation/Fran...

Un élément devra être considéré comme équivalent à un élément d'une revendication si, dans le contexte de l'invention revendiquée,
a) l'élément examiné remplit sensiblement la même fonction pour produire sensiblement le même résultat que l'élément revendiqué, et
b) la différence entre l'élément revendiqué et l'élément examiné n'est pas essentielle dans la revendication telle que la comprend l'homme du métier à la date de la contrefaçon.
https://www.aippi.org/download/comitees/175/RS175French.pdf

The claims are the crucial part as far as enforcing a patent goes – an alleged infringing article or process has to use every part (or “integer”) of a claim to infringe the patent.
http://www.cs.bham.ac.uk/~mdr/teaching/modules04/security/So...

In reality, the "fences" often consist of complex layers of definitions of different elements (or "components" or "features" or "integers") of differing complexity, substitutability and ingenuity
http://www.jurisdiction.com/since.htm