Nord de Guerre - EPSG:27500

WKT

PROJCS["Nord_de_Guerre", 
	GEOGCS["GCS_ATF_Paris", 
		DATUM["D_ATF", 
			SPHEROID["Plessis_1817", 6376523.0, 308.64]], 
		PRIMEM["Paris_RGS", 2.337208333333333], 
		UNIT["Grad", 0.01570796326794897]], 
	PROJECTION["Lambert_Conformal_Conic"], 
	PARAMETER["False_Easting", 500000.0], 
	PARAMETER["False_Northing", 300000.0], 
	PARAMETER["Central_Meridian", 6.0], 
	PARAMETER["Standard_Parallel_1", 55.0], 
	PARAMETER["Scale_Factor", 0.99950908], 
	PARAMETER["Latitude_Of_Origin", 55.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["Nord_de_Guerre", 
	BASEGEOGCRS["GCS_ATF_Paris", 
		DATUM["D_ATF", 
			ELLIPSOID["Plessis_1817", 6376523.0, 308.64]], 
		PRIMEM["Paris_RGS", 2.337208333333333, 
			ANGLEUNIT["Degree", 0.0174532925199433]], 
		CS[ellipsoidal, 2], 
		AXIS["Latitude (lat)", north, 
			ORDER[1]], 
		AXIS["Longitude (lon)", east, 
			ORDER[2]], 
		ANGLEUNIT["Grad", 0.01570796326794897]], 
	CONVERSION["Lambert_Conformal_Conic", 
		METHOD["Lambert_Conformal_Conic"], 
		PARAMETER["False_Easting", 500000.0], 
		PARAMETER["False_Northing", 300000.0], 
		PARAMETER["Central_Meridian", 6.0, 
			ANGLEUNIT["Grad", 0.01570796326794897]], 
		PARAMETER["Standard_Parallel_1", 55.0, 
			ANGLEUNIT["Grad", 0.01570796326794897]], 
		PARAMETER["Scale_Factor", 0.99950908], 
		PARAMETER["Latitude_Of_Origin", 55.0, 
			ANGLEUNIT["Grad", 0.01570796326794897]]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["EPSG", "27500"]]

Data from @esri/proj-codes

{
  "wkid": 27500,
  "latestWkid": 27500,
  "gcsWkid": 4901,
  "macro": "PE_PCS_ATF_NORD_DE_GUERRE",
  "name": "Nord_de_Guerre",
  "wkt": "PROJCS[\"Nord_de_Guerre\",GEOGCS[\"GCS_ATF_Paris\",DATUM[\"D_ATF\",SPHEROID[\"Plessis_1817\",6376523.0,308.64]],PRIMEM[\"Paris_RGS\",2.337208333333333],UNIT[\"Grad\",0.01570796326794897]],PROJECTION[\"Lambert_Conformal_Conic\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",300000.0],PARAMETER[\"Central_Meridian\",6.0],PARAMETER[\"Standard_Parallel_1\",55.0],PARAMETER[\"Scale_Factor\",0.99950908],PARAMETER[\"Latitude_Of_Origin\",55.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"Nord_de_Guerre\",BASEGEOGCRS[\"GCS_ATF_Paris\",DATUM[\"D_ATF\",ELLIPSOID[\"Plessis_1817\",6376523.0,308.64]],PRIMEM[\"Paris_RGS\",2.337208333333333,ANGLEUNIT[\"Degree\",0.0174532925199433]],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Grad\",0.01570796326794897]],CONVERSION[\"Lambert_Conformal_Conic\",METHOD[\"Lambert_Conformal_Conic\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",300000.0],PARAMETER[\"Central_Meridian\",6.0,ANGLEUNIT[\"Grad\",0.01570796326794897]],PARAMETER[\"Standard_Parallel_1\",55.0,ANGLEUNIT[\"Grad\",0.01570796326794897]],PARAMETER[\"Scale_Factor\",0.99950908],PARAMETER[\"Latitude_Of_Origin\",55.0,ANGLEUNIT[\"Grad\",0.01570796326794897]]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"EPSG\",\"27500\"]]",
  "description": "Nord de Guerre",
  "authority": "EPSG",
  "version": "2.1(3.0.1)",
  "deprecated": "no",
  "areaname": "France - Alsace",
  "extent": {
    "slat": 47.42,
    "nlat": 49.07,
    "llon": 6.84,
    "rlon": 8.23
  }
}