Hi,

For your information, don't waste time converting BYO maps, they are out of date and won't be updated as IGN french maps.
Futhermore, the tool "Cbyo" only works with Bayo's maps released before 2005.
Now, IGN sells its own hike preparation software (Georando) and does not distribute its maps anymore (in a competitive setting). Unfortunately, "Georando" is not as good as "Carto Eplorer".