So - I was chatting earlier to a 'friend' in the local tax office who told me that there is currently a general 'purge' (?) on the non-declaration of overseas bank accounts (opened, closed or used) and life assurance policies (assurance vie) held by French fiscal residents. As you'll probably know, the fines and penalties for non-declaration are pretty huge and are multiplied by the number of years of non-declaration - all the info re fines is on the impots.gouv.fr website.
I know it's only two little boxes on the main 2042 form - bottom of page 4, boxes 8TT & 8UU but..better safe than sorry. If you declare on-line you're prompted to fill in the info about life assurance and attach forms 3916 for each bank account opened, closed or used. They're not interested in the amounts held/invested - just the details of the accounts and policies.
Such fun!