Camping Gaz and Coleman are now owned by the same people so Coleman should have access to Camping Gaz's distribution network in France, Spain and Italy. Hopefully that means EN cartridges will be easier to find. I haven't done much touring this year, and I've mainly been in the UK, but the few times I've seen gas canisters on sale at campsites they've been selling both Camping Gaz and Coleman. (That's the Coleman EN screw-on cartridges not the proprietary ones they used to make).
If you want an insurance against not finding a gas cylinder then t would be worth considering getting a little 'sodacan' style meths stove. 'Alcool a quemar' is widely available. The
Triad stove from backpacking light.co.uk for example: weighs only 28g and includes its own foldaway pot supports. May not be what you'd choose for regular use, but looks good for a fallback.