Postgis assign projection problem

I have imported a shapefile into postgis
Shapefile type: ArcZ
PostGIS type: MULTILINESTRING[4]
Shapefile import completed.

The postgis import does not set the projection, even if a prj file exists. So I get a message to assign projection, what I do : Lambert 93-RGF93

Here are the debug Debug messages

After choosing Assign :
Warn VectorLayer: assign projection method isn't supported.

double clic in legend, open properties (it's the previous and last line that worry me)
Debug OgrLayer: Geometry data was reprojected and can't be saved to the source. Debug Table: Index Out of Bounds