As the 19-nation currency area finally emerges from years of crisis, there is agreement in many eurozone capitals that it must be buttressed to better weather future economic storms - but not all countries agree on how best to do it. Moscovici said a "real window of opportunity" opened last year with the election of reformist President Emmanuel Macron.
The French leader has set out an ambitious vision for European reforms, including having a separate eurozone budget and finance minister. But the window "will probably close" in the run-up to next year's European Parliament elections, Moscovici said.
The left-right "grand coalition" reached in EU powerhouse Germany last week between Chancellor Angela Merkel and the Social Democrats is cautiously supportive of Macron's reform proposals.