> then that government would have political power to force changes at the EU level

The ECB - like most central banks - is given completely autonomy from decisionmakers in the EU and EC. France's politician weight in the EU has little bearing on what the ECB or the IMF decides if France defaults.

In 2006-07, Italy and Spain were similarly sized economies to France, but when they defaulted due to the Eurozone crisis, their entire autonomy on budgetary decisions was stripped despite also being large and (then) politically powerful nations within the EU.

France needs to rightsize it's social benefits to be comparable to it's EU peers like Germany or Netherlands ASAP or they will be forced to with no say during a default.