The French President says the backstop is not just a technical mechanism but the protection of stability in Ireland.
Emmanuel Macron was speaking in Paris before a meeting with the British Prime Minister to discuss Brexit.
Boris Johnson wants the backstop removed and a new deal negotiated.
The French president says a new Brexit withdrawal agreement isn't possible within 30 days.
He added that it's up to the UK to decide how it wants to leave the EU.
The Brexit Storm
Meanwhile, Tanaiste says, unfortunately, Ireland lies in the eye of the Brexit storm.
Simon Coveney is visiting five European capitals to make certain of support for Ireland's position on Brexit.
Speaking in Copenhagen "Of course we want to try and find a way to get a deal before the end of October."
"There are parameters that we have to operate within - there are commitments that have been made that need to be followed through on."
"Ireland, unfortunately, is in the eye of the storm here because it's issues on the island of Ireland that seems to be the source of disagreement at the moment."