These are necessary for what was at one time considered the "US" version of the
build. Based on the fact that you are in France, and also because different builds
are usually not confined to a geographic area, I'm thinking now that the
version you have is the "thin wheeled" version. At this point I'm not sure
which version came first.
Unfortunately, these 5-long axles and the yellow pin bricks are not the only
differences (see images below), so this is going to need a full-fledged alternate
exchange.
France, Auvergne-Rhône-Alpes
USA, California
)
)