I have recently had the pleasure of speaking with an extremely disagreeable French civil servant (fonctionaire d’état), because I had the cheek to ask if I could apply for French citizenship and still retain my American (US) citizenship. He informed me that because the United States so unreasonable (he paused, and continued) on this subject, France responded in kind. I went on to explain that my children all had dual citizenship with passports from both countries (My wife is French and our family has lived for prolonged periods in both countries, though we no reside in France). He went on to explain that our children would benefit from this Dual nationality until the age of 18 when they would have to choose to which country they would owe their allegiance. I then made the mistake of asking what would happen if at 18 they did not make that choice just kept on using their 2 passports. To which he curtly replied “the French Government would revoke their passports. Now I lived in France for some time now and this country doesn’t seem to me to be that vindictive. Could this gentleman be right, or as I suspect, just had a bad day and did not wish to respond by phone?
Could somebody please tell me where I could find the text on dual nationality between the United States and France?

LOL he had a normal day!!

If you have lived in France you you will understand more than anyone else, the nature of the civil servant and the mentality behind the guichet and 'les Yankees' .
If your children have dual nationality! They are not in the obligation to relinquish either passports, I recently applied for (and gained in 2008 under 2 months) my dual nationality for France (being British since birth, but born in Paris with a French mum). I did not warn Britain of my intentions and the French authorities where only interested in the correct paperwork (giving other nationalities not being one of them). I applied for this at the age of 29!
Many of my friends with dual nationality with France have never chosen, or sworn allegiance to either country and enjoy free travel from the states and France under both passports and are now in their 30's.
The united states, Canada and most EU countries allow dual Nationality with France and even triple (French, Canadian, US nationality) so your children will be fine.

If you have a french wife with children of dual nationality, and you have lived in or are currently living in France, you should be able to obtain dual nationality, without too many problems, if you work in France then the company that employs you can help you. For information I would go to the French Consular, the mairie and the US embassy. But before doing that I would go to the site below, it should answer all your queries!!
If you copy paste the link bellow it will tell you all (it is in french though):

http://www.diplomatie.gouv.fr/fr/les-francais-etranger_1296/vos-droits-demarches_1395/nationalite-francaise_5301/index.html

And there is a short perspective of the American view here

http://travel.state.gov/travel/cis_pa_tw/cis/cis_1753.html

I hope that this is of some use to you and as they say in France: "Bonne Merde" ;)