Currently, most migrant boats set off from the northern French coast near Calais and Dunkirk.
More than 25,700 people made the journey in small boats this year, according to data compiled by PA.
Mr Dumont said that migrants must be moved away from the Channel and into health centres in the middle of France.
“My message to the French authorities, which I said to them a few minutes ago, is that we need to understand that if the migrant is in Calais – or around the Channel – they will try to cross the Channel”, he said.
“We need to move them, even if by force, to health centres in the middle of France.”
The UK has offered to send police and border officials to France to help them prevent migrants from crossing the Channel.
However, Mr Dumont said that France cannot accept the UK’s offer due to “the question of sovereignty”.
“I heard Priti Patel’s comments yesterday claiming that she offered France British troops – that is not possible because of the question of sovereignty,” he said.
“But if the soldiers and patrols are in Calais with the migrants they will still find a way to cross, because you cannot monitor 200km of shore at the same time.”