This is often translated as 'introduction of third parties'. See previous questions:

http://www.proz.com/kudoz/french_to_english/law_patents/4867...

http://www.proz.com/kudoz/french_to_english/law:_contracts/2...

The ability to pass on liability to a third party under French law is permitted under French substantive law in certain circumstances (such as where a contractual guarantee exists or where liability is joint and several). As a procedural matter it is governed by the rules relating to l’intervention forcé. This comprises the possibility of a defendant requiring a third person to become a party to the proceedings issued by the plaintiff as a co-defendant provided that the defendant has a principal cause of action against such third party or can show that there is an interest in having the judgment binding upon such third person. One particular example of this right is where a party to litigation before the French courts can require a third person that has guaranteed the litigious debt to become a party to such litigation (appel en garantie) and thus be bound by any judgment issued by the courts.
http://www.iclg.co.uk/index.php?area=4&country_results=1&kh_...