@houtslager caution..long reply.
Non, tu n'es pas fou
But, as Clogs said, things take longer here, and it really pays off to speak and understand french well.
Nice project, if you do most / all of it yourself.Very expensive if french "tradies" do any of it for you.
Tip..When I arrived in France in 90, my french was virtually non existent, such that although I drink my coffee black with no sugar, I spent the first six months , drinking white with sugar at cafés, because I did not know how to say "no milk or sugar thank you" in french. I had met SWMBO ( who is breton french ) within the first 10 days, thankfully she spoke English.
I learned my basic first "conversational french" by watching french TV, Canal+ at the time would show movies in "VO" ( Usually English, which I subsequently learned was often badly or approximately translated ) and later that same week in French. Dirty Harry Monday evening in English, the same movie on Wednesday evening in French, that sort of thing, with the occasional "correction / explanation" from "Madame".
She, like very many french, had a collection of BD ( bande dessinée = comic books ) Asterix and so on. Also a few paperbacks in Bi-lingual, Agatha Christie etc. I began learning to read french via these. It took me three years to become fluent in everyday spoken french, another two to become fluent in technical , scientific and legal french ( 3 court cases brought by us, 3 wins, each time I did not use lawyers ).I don't say that to blow my own trumpet, but to point out that it is possible.
If you treat learning a new language as you learnt your mother tongue, you'll do much better, learn it like a child, begin with the child level stuff. Yes I know Dirty Harry isn't kids stuff, but the cartoons were on in the mornings, and I'm not a morning person.
Don't watch UK TV..you'll not learn your new language by watching and hearing the one you already know.
Many ex-pats do just that, ( there is a magazine for them here in Brittany, with loads of ads for UK TV systems ) and never really integrate, nor achieve the fluency that would allow them to do so, one can learn a great deal about what is going on , by overhearing conversations.
If you are going to be running a business here, decide if you want to start small ( micro-entreprise ) or become a french LTD ( SARL )..
pm me for the name of a scammer to avoid like the proverbial plague, a supposed, he claims "chartered accountant" / "expert comptable" who is neither, ( a Brit ) who preys upon the "ex-pat" community and who I and SWMBO spent 18 months extricating one couple who he scammed from the french tax ( fisc ) and social security services ( URSSAF ) who had sent the bailiffs to seize their house and their bank accounts.He had told the couple that he had taken care of it all, the result was that they were unknowingly ( upon his "expert advice" ) committing tax and social security fraud here, and had been doing so for 6 years before the french authorities decided to take a look at them.
As a result of helping them, I became friends with ( and unofficial translator for ) the heads of a couple of french tax fraud office divisions, one where the couple lived, and one where I live.
He is still running his scam , with 100s of "ex-pat" "clients".
According to my friends at the tax offices, they are now getting around ( since Brexit ) to looking into the ex-pat communities ( of all countries ) or the dual nationality holders in France, but the language barrier and the fact that many "ex-pats" trade and work amongst themselves in their own anglophone communities means that it takes them longer to gather evidence before taking action. They already are understaffed to deal with the french, whose own communities ( like the forains I used to work with ) already have thriving "black economies" of their own.Both my tax inspector friends inform me that 90% of their investigations are sparked by denunciations ( written or phoned, often anonymous ), as an "incoming foreigner" you can never know whose nose may be put out of joint by your merely arriving and opening a business, or buying a building which maybe they had their eye on ( even if they could never afford it ) which makes you more likely to be the subject of speculation and maybe a phone call, than a local person.
Depending on your age, the official french language requirements ( to set up a business and obtain residency if your or your partner are both Brits ) are easier than they seem at first glance. Then again , if you are Norn based, you may well have an Irish passport, ( aren't they just grand
) so all is good re travel and right of abode and work / running businesses.
France ( mainland ) can be good ( despite clogs's experience ) , but can be ( and is frequently ) extremely frustrating, with many faults, but, from what I remember ( and see nowadays of the UK ), it is by far preferable to living in mainland Britain.
The french overseas areas are even better, what is not to like about
https://en.wikipedia.org/wiki/Overseas_France
. I found this on Le Bon Coin, a delepdated 3 bed house with a 900m² she'd attached 
