EPSG Library · Europe

EPSG:2154 — RGF93 v1 / Lambert-93

Source: EPSG Dataset via PROJ 9.5.1 · Updated 2026-10-05

Summary

EPSG:2154 (RGF93 v1 / Lambert-93) is a projected coordinate reference system on the Reseau Geodesique Francais 1993 v1 datum using the Lambert Conic Conformal (2SP) method, with coordinates in metres. Area of use: France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica).

Type: projected
Datum: Reseau Geodesique Francais 1993 v1
Units: metre
Axes: X, Y

Definition

EPSG:2154 as published in the EPSG Dataset (PROJ 9.5.1).
Property	Value
EPSG code	EPSG:2154
Name	RGF93 v1 / Lambert-93
Type	Projected CRS
Datum	Reseau Geodesique Francais 1993 v1
Ellipsoid	GRS 1980 (a = 6,378,137.000 m, 1/f = 298.257222)
Prime meridian	Greenwich
Projection method	Lambert Conic Conformal (2SP)
Axes	Easting (X, east, metre); Northing (Y, north, metre)
Scope	Engineering survey, topographic mapping.
Bounding box	-9.86° to 10.38° longitude, 41.15° to 51.56° latitude

Area of use

France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica).

Projection parameters

Lambert Conic Conformal (2SP) parameters.
Parameter	Value	Unit
Latitude of false origin	46.5	degree
Longitude of false origin	3	degree
Latitude of 1st standard parallel	49	degree
Latitude of 2nd standard parallel	44	degree
Easting at false origin	700,000	metre
Northing at false origin	6,600,000	metre

Example coordinates

A WGS 84 point at longitude 0.26°, latitude 46.355° (inside the area of use) has these coordinates in EPSG:2154:

Computed with PROJ using the EPSG default operation: axis order change (2D) + Inverse of RGF93 v1 to WGS 84 (1) + Lambert-93.
Axis	Value	Unit
X	489,353.588	m
Y	6,587,552.204	m

At this point the projection scale factor is 0.99905513 and the grid convergence is -1.988165°.

Open this conversion in the coordinate converter

Transformations to WGS 84

Candidate operations from the EPSG Dataset, best first as ranked by PROJ.
Operation	Accuracy	Area of use
axis order change (2D) + RGF93 v1 to WGS 84 (1) + axis order change (2D)	1 m	France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica).

Transformations change the datum, so each has an accuracy and an area of use. Choose the most accurate one that covers your data and record its name. See datum transformations.

Definitions and downloads

PROJ string

+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +units=m +no_defs +type=crs

A PROJ string cannot carry every EPSG detail (axis order, datum ensemble, transformations). Prefer WKT2 or the EPSG code itself.

Proj4js definition used by the converter

+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +units=m +towgs84=0,0,0 +no_defs

Datum shift from RGF93 v1 to WGS 84 (1) (EPSG accuracy 1 m), the best single Helmert operation for this area of use. Where PROJ prefers a grid-based or multi-step operation (see the table above), results can differ by up to that operation's accuracy.

WKT2:2019

PROJCRS["RGF93 v1 / Lambert-93", BASEGEOGCRS["RGF93 v1", DATUM["Reseau Geodesique Francais 1993 v1", ELLIPSOID["GRS 1980",6378137,298.257222101, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4171]], CONVERSION["Lambert-93", METHOD["Lambert Conic Conformal (2SP)", ID["EPSG",9802]], PARAMETER["Latitude of false origin",46.5, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8821]], PARAMETER["Longitude of false origin",3, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8822]], PARAMETER["Latitude of 1st standard parallel",49, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8823]], PARAMETER["Latitude of 2nd standard parallel",44, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8824]], PARAMETER["Easting at false origin",700000, LENGTHUNIT["metre",1], ID["EPSG",8826]], PARAMETER["Northing at false origin",6600000, LENGTHUNIT["metre",1], ID["EPSG",8827]]], CS[Cartesian,2], AXIS["easting (X)",east, ORDER[1], LENGTHUNIT["metre",1]], AXIS["northing (Y)",north, ORDER[2], LENGTHUNIT["metre",1]], USAGE[ SCOPE["Engineering survey, topographic mapping."], AREA["France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica)."], BBOX[41.15,-9.86,51.56,10.38]], ID["EPSG",2154]]

Downloads

2154.prj — ESRI WKT for shapefiles
2154.wkt — OGC WKT2:2019

FAQ

What is EPSG:2154?

Where can EPSG:2154 be used?

Its area of use is: France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica).

Is EPSG:2154 in metres or degrees?

EPSG:2154 is projected, so coordinates are easting and northing in metres, not degrees.

How do I convert EPSG:2154 to latitude and longitude?

Transform from EPSG:2154 to EPSG:4326 (WGS 84). In GeoCAD Bridge open the coordinate converter with EPSG:2154 preselected, enter easting and northing, and choose WGS 84 as the target.

How accurate is the transformation from EPSG:2154 to WGS 84?

The most accurate EPSG transformation listed here is “axis order change (2D) + RGF93 v1 to WGS 84 (1) + axis order change (2D)”, with a stated accuracy of 1 m for France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica).. Always check the area of use before applying it.

Coordinate systems

Articles

Tools

References

IOGP. EPSG Geodetic Parameter Dataset, epsg.org/crs_2154.
PROJ 9.5.1 / pyproj 3.7.2, used to compute every value on this page.

Cite this page

GeoCAD Bridge. “EPSG:2154 — RGF93 v1 / Lambert-93.” GeoCAD Bridge EPSG Library, updated 2026-10-05. https://www.geocadbridge.com/epsg/2154/