
Marine Nationale photo, FS Lieutenant_de_vaisseau_Lavallée, one of seven 80 meter (263′) 1,270 ton D’Estienne d’Orves-class avisos or corvettes being used as Offshore Patrol Vessels that are to be replaced.
France has been building a lot of Coast Guard Cutter like vessels recently and it looks like they will be building more. Naval News reports:
Ten new generation OPVs will replace the A69 type (D’Estienne d’Orves-class) PHM (formerly Aviso / light frigates and then reclassified as patrol vessels) based in Brest (Atlantic Coast–Chuck) and Toulon (Mediterranean- Chuck) and the PSP patrol boats based in Cherbourg (English Channel-Chuck).

Cormoran (P677), one of three 23 knot, 54 meter (177′), 477 ton French navy PSP patrol boats. Brest, Finistère, Bretagne, France. Photo by Gary Houston (Notice the striping similar to that carried by USCG cutters)
The one billion Euro contract awarded to Naval Group (formerly DCNS) would mean a unit cost of approximately 100M Euros ($112M).

Rendering of the future “POM” OPV of the French Navy.
Apparently, based on price, they will be larger than the six recently contracted 70 meter, 22knot “POM” patrol vessels. (224 million euros, 37.3 Euros or about $42M each)
Not long ago Naval Group and ECA group was given a 2B Euro contract to produce twelve 2800 ton Mine Countermeasures ships for the Dutch and Belgium Navies. Given that ship yard prices for similarly complex ships tend to be proportional to their displacement, and that these ships are probably less complex than the MCM, I would suspect that the new OPVs will be about 1,680 tons. That would make them similar in size to the WMEC 270s. Given the ships they are replacing and the character of recent construction, they will probably a bit longer and faster than the 270s, probably about 90 meters long, at least 20 knots but probably more, with a flight deck for a medium helicopter like the NH90, a hangar for a smaller helicopter similar to the H-65 and probably the 700 kilo rotary wing unmanned aircraft planned for POM. There will probably be space for containers. The crew will be small by Coast Guard standards, maybe less than 50, but will likely have additional accommodations for about 30 in addition to the crew.
Weapons: It will almost certainly have the Nexter Narwhal 20 mm cannon and .50 caliber machine guns, but there is no indication if they will have anything larger. French Navy vessels that wear the “Coast Guard Stripe” apparently have no weapons larger than .50 cal. (12.7mm). The seven A69 corvettes to be replaced have 100mm guns, but these ships were not originally designed as law enforcement vessels, and once also had Exocet anti-ship cruise missiles, so a medium caliber gun may not be seen as a requirement. If they wanted to put a medium caliber gun on these at small cost, the French Navy almost certainly has numerous, surplus, still very effective 100mm guns, but their newer ships mount the Super Rapid 76mm, which weighs less than half as much. The quoted French Ministry of Armed Forces statement might suggest they see a need for stronger armament.
“In a context marked by the increase in maritime traffic and the toughening of threats at sea, patrol boats fulfill a very broad spectrum of missions: support for deterrence, presence in areas of sovereignty and interest, evacuation, protection, escort and intervention in the framework of State action at sea.”
The linked Naval News post mentions the European Patrol Corvette program as a possible basis for this program, but given their projected displacement of 3000 tons, they would be beyond the projected budget.

There is a good chance these ships will emerge as an upgraded version of the the 87 meter (285′), 1450 ton L’Adroit (above) which was sold to Argentina along with three similar ships. The Naval News post indicates that the projected cost of the new OPVs is almost twice the cost so of the L’Adroit class, but they were designed for export. Meeting Navy standards with better equipment and improved survivability can substantially increase cost. When the Royal Navy built their River Batch II OPVs it was based on OPVs originally ordered by Trinidad and Tobago. Modifying the design to meet Royal Navy standards caused a great increase in price. The three vessels were built for Trinidad and Tobago cost £150M pound (US$237.8 M). When the Royal Navy contracted for three ships that met their standards, the outwardly almost identical ships came in at a fixed price of £348 million–a few years later, but more than double the price.