Not sure about that way around, but when I worked on Guernsey, large new builds used lots of French plumbers, I was friendly with a few and they reckoned they were earning about 4 times what they would get in France, they were on less than they would get here
It partly depends on what question you're asking - but post Brexit its difficult would be the simplest answer.
If you mean move over and set up as a plumber - its not easy. You need a Visa/Work Permit and that requires either savings or a business plan - UK qualifications are no longer recognised so you can't set up without doing the French qualifications - plus post Brexit there's less Brits moving over so the market is shrinking.
Trading from the UK and popping over isn't formally allowed anymore - that and local trades have to provide Insurer backed 10 year guarantees. In effect its still possible on the quiet - but the work is basically "DIY" given there's no insurance and no French "qualifications" so .........