I live in Reunion Island, a french department overseas, and so I can't buy softwares online. How can I buy?

Adobe Resellers http://adobedealreg.force.com/PartnerSearch?lang=en

-http://www.adobe.com/content/dam/Adobe/en/products/creativecloud/cc/pdfs/cc-availability-matrix.pdf

If they do not sell in any of the local stores and you are unable to purchase online then you probably need to leave the area to find a place that sells the software or has somewhere in which purchasing online is an option