Reactivate your account or life insurance contract straight away to avoid your money being deposited in Caisse des Dépôts from July 2016.
For life insurance contracts with a policy holder who has been deceased for less than 10 years, contact the Association for the management of information on insurance risk (AGIRA), which will consider information requests from all insurance bodies. This request must be made by post. http://www.agira.asso.fr/content/comment-saisir-lagira
To contact Caisse des Dépôts, wait until January 2017: an online search service will be made available to you and will make your efforts easier.