Moscovici appealed, however, to the other presidential candidates, who include Independent Emmanuel Macron and Republican Francois Fillon, to prove themselves to the electorate and, ultimately, make a stronger case for remaining in the EU.
"The other candidates need to have a stronger campaign and show that they are credible to propose a future that is likeable for the French.
"I think the rise of Le Pen is a result of the disappointment in other candidates, so I urge them to make a strong proposal for France, and as well for Europe, and for France in Europe."
Moscovici pondered – but quickly dismissed – the notion of a win for Le Pen, who has been gaining ground on her rivals in recent polling.
"If Marine Le Pen comes in office, if she asks for a referendum on Frexit, what would Europe be about? Europe was founded precisely in order that France and Germany and others work together in a common project. But this won't happen – it's just to say how crazy it will be if she is elected – that is why precisely it cannot happen, it won't happen, it must not happen"
France will go to the polls for first-round elections in April. The second-round vote is due in May.