OK, this is the mandatory-ELT and mandatory-oxygen amendment that has been in the proposal stage for a couple of years.
Fuji is right that nearly all of the UK GA fleet is now illegal to fly to France. There has not been any real publicity given to this.
It applies to G-reg only, but N-reg have to carry ELTs anyway and the FAA mandates oxygen use above certain altitudes.
The curious thing, and I am away from home and don't have time to look up the "K" references, is that the CAA had assured people that a portable ELT i.e. an EPIRB would be acceptable. A fixed ELT makes sense for the USA with its large expanses of empty land but is plain stupidity for the UK where by far the greatest risk is ditching and you want the ELT with you in the raft. Nearly all CFITs are totally fatal. A portable ELT does away with the silly installation cost too - I was quoted 2000 quid for the paperwork to install a different kind of ELT to my N-reg and a G-reg would be roughly similar; there are legally significant (if hardly practically relevant on a nonpressurised hull) structural issues on the antenna mounting. The cost of fitting a fixed ELT i similar to fitting a Mode S transponder.
Mandatory oxygen is not a problem for the UK; only on airways routes would one (generally) need it and anybody doing that can buy a portable kit for a few hundred quid.