SPIP is a multilingual open-source CMS created in 2001, and a lot of non-profit use it as their website tool in France and other countries. Is it planned, or do you heard about some people willing to use civicrm together with SPIP ? Many thanks in advance, Cyril
From what I can see, it seems that SPIP is a CMS and not a CRM. While there are no plans for native integration between CiviCRM and other CMSes beyond the four currently supported, many organizations still integrate CiviCRM with their existing CMS. Simple integration options include remote profile submissions using snippets. You can also use remoteform, which also works with contribution pages.
If you wanted a deeper integration, you could use CiviMRF, but that would take development work.