Employer's NI is at 70% this year. It means that a workman paid the minimum wage of around 10€-11€/hr is charged out at 400€/day.
Back in 2007-8 this was 250€/day and the quality of the workmanship was crap. The really good work we had done was done by Brits. My uncle was born in France in the Somme and just could not understand the mentality in the SW.
You can, or could, deduct 10% of the bill for snagging. But, if the work qualifies for a credit impôt you have to pay 100%.
The scheme seems to be designed to keep firms in business, provide tax revenue - and stop cash in hand - and not necessarily the best for the building.
A friend in his 50s said that he used to do business on a handshake, but no more, as he's been done too many times. And he's French.
We bought a village house in '07 for 160€, spent 120k€ on renovations, and due to the slide in the pound never got the pool we' d planned, and sold in '18 for 155,500€.
At Dec' 06 values we had 440k €, but the pound dropped to parity, which made a huge difference.
I'd be tempted to use a management company for a rental, like Sykes in the UK, and you'll need to take advice from a firm of international accountants which won't come cheap.
The French finances publics are very helpful, but are having massive retirements at the moment. I used to know all the local tax inspectors, and with the introduction of a Paye type system in France, in place of prior year there have been teething troubles.
I noticed that income in £ on one form hadn't been pulled through to the general form and the controller I saw was quite young, and had never had dealings with foreign income before and asked me which box it should go into on the main form. Despite all the distancing etc, we ended up pouring over the 1-inch thick tax manual together.
Obviously Covid hasn't helped.
I live as a tenant in a house that has suffered bad conversion as a result of the tax credit. Double glazing has been installed for the 25% credit where the single glazing allowed the sun to heat the house. Insulated shutters were available, expensive and only got a 5% or 10% credit, if that. The result is a sweaty humid hermitically sealed box that is damp in both winter and summer.
You could well end up having to shell out money to undo work that should never have been done in the first place.
Good luck