“You cannot have all the advantages of being a member of the club when you are out of the club. I think that our British friends who invented clubs can understand that,” he told the BBC.
He was speaking at Davos, where Theresa May is due to speak later.
Mr Moscovici is a former French finance minister and is in favour of greater integration within the EU.
“I am convinced that it is not an example to follow, that it’s not positive neither for us neither for the UK.”
Mr Moscovici said the split would be damaging “because we are and we must remain strong partners. To us you must understand that it is also a wound”.
On Wednesday, the head of the International Monetary Fund, Christine Lagarde, said there was likely to be further “pain” ahead for the UK as Brexit approached and that any deal with the EU would “not be as good” as membership.
Mr Moscovici reiterated that view: “Brexit means Brexit, which is to say that it is not the same to be out than in, and it cannot be better to be out than in, because it cannot be so.
“We need to re-invent a new kind of relationship that I hope to be close, balanced and positive but that’s the outcome of the negotiations not the starting point.”
However the BBC’s Kamal Ahmed said Mr Moscovici’s words could indicate there was still some room for manoeuvre.
Asked whether Britain might be able to retain some privileged access to the single market, Mr Moscovici said: “It’s not a denial from my side; but nobody can speculate about that – we have to move step by step.”
Kamal Ahmed, said Mrs May, speaking at the World Economic Forum for the first time as UK prime minister on Thursday, would receive a mixed reception at Davos since many of the business people present had opposed Britain leaving the EU.