The difficulties of a French “No” vote in their upcoming referendum are nicely summarised by Netlex, though sadly in French, and I don’t have time to do a full translation. You could try and make do with Babelfish, but it’s a bit rubbish. Short(ish) highlight bit:

“si les conservateurs reviennent au pouvoir, ils ont �galement pris l�engagement d�obtenir la ren�gociation de leurs engagements europ�ens, tout comme pr�tendent le faire les partisans du �NON� en cas de victoire, mais pour des raisons exactement inverses. En effet, les conservateurs trouvent que les fameux �droits sociaux� sont un obstacle � la cr�ation d�emplois, et qui freinent le d�veloppement �conomique de la Grande-Bretagne.

“[A] ‘Conservative Government will negotiate to restore our opt-out from the European Social Chapter and liberate small businesses from job-destroying employment legislation’.

“Voil� qui donne une id�e de ce qui attend les Fran�ais qui voudront ren�gocier les dispositions de la Constitution, quand ils vont devoir affronter les Etats qui d�fendent des positions diam�tralement oppos�es aux leurs.

“..Il est donc tr�s clair qu�en cas de victoire d�un �Non� fran�ais, l�Europe va entrer dans une p�riode de crise, et d�instabilit�, et ceux qui pensent sans doute sinc�rement, mais tr�s na�vement, que les Fran�ais seront en mesure d�imposer une �Constitution sociale� � des pays europ�ens dont la majorit� n�est pas de Gauche, vont aller de surprises en d�convenues.”

Approx paraphrased translation:

If the Tories get in, they’ve said they’ll renegotiate with the EU, just as the [socialist] supporters of a French “No” vote in the upcoming referendum have said – but for precisely the opposite reasons. The Tories see the social rights the EU preserves as holding back the UK’s economic growth – and so we see what will await those French who want to renegotiate the constitution to gain more rights from countries whose ruling parties want less.

It is therefore clear that in the event of a “No” vote Europe will enter a period of crisis and instability, and those who wish to impose a “Social Constitution” on countries whose majority is not left [or those who wish to remove rights from countries which are] will be in for a severe disappointment.

Even shorter paraphrased translation: Renegotiation of the constitution may be impossible.