One subtle difference - the French IR "lite" will be so far as I understand it, ICAO compliant - so useable worldwide, whilst the IMCR isn't and won't be.
Individual states have the right to do their own ICAO compliant things and because it's ICAO compliant allow it to be used worldwide.
There are a lot of examples of this - for example the UK has BCAR 31 which is an ICAO compliant code for large public transport hot air balloons.
G