Two additional vessels are being deployed in what the French Coastguard describes as an “unprecedented” move.
It follows criticism of the French response to the incident in November 2021 in which 27 people drowned trying to cross to the UK in a dinghy.
More than 40,000 people have made such crossings this year – a record number.
The French Coastguard says the Lapérouse survey vessel has just arrived in the port of Calais, while the Kermorvan patrol ship will be there in the next few days.
It says that their deployment will strengthen the coastguard’s rescue capabilities in the Channel-North Sea sector.
Last month, the UK agreed to increase payments to France by £8m ($10m) more a year to £63m to try to stop channel crossings in small boats.
The money will pay for increased surveillance of French beaches, while UK police officers will also be able to observe patrols within France.
It is thought French officers patrolling the coast will rise in number from about 250 to 350 over five months.
The higher numbers of migrants making the crossing this year of the Channel (known as La Manche in France) has been partly blamed on a big rise in the number of Albanian nationals making the journey.
So far this year 12,000 Albanians have arrived in the UK using small boats, compared with just 50 in 2020.
