In my experience working in the building trade here the tradesmen are very picky about the way they do things and a proper electrician is putting out quality, safe work. I've seen a lot more rubbish work in the UK, but one of the problems here is there are so many old systems that have been fudged. My house was declared as unsafe and my supply was cut by ENEDIS soon after i moved in, for safety reasons, and yet there had been a 93 year old woman living here before us.
The quality on site is probably due to a 35 hour work week not including the massive lunch breaks they take and the fact that they are paid like crap! Cards in sparks jobs here are basically only a little bit above minimum wage, whereas self employed guys are charging anywhere from 200-700 a day. Cards in jobs are averaging around 1700euro before tax - minimum wage (called SMIC) is 1500 a month.
One spark wanted 900 euro to fix a consumer unit to the wall in my mates house, no wiring done. OK, the big 4 rail Le Grand units are like 600 euro but he wanted 900 in total just to literally put 4 screws on the wall and put the tails in, half hours work.
I just know from doing my own plumbing in my own house that the fittings are atrocious. Every single part of them. The most expensive toilet cistern mechanism you can buy is garbage quality. The fittings are crap, whether from a brico or a professional plumbing place (i've used both), the compression fittings almost always leak without ptfe when the entire point of a compression fitting is you shouldn't need ptfe. Horrible all round. The plastic stuff is crap too.
A professional plumbing centre told me you were only allowed to solder gas joints and not water joints due to the pressure. He said you used to be able to but the rules had changed (this was in 2017.) Not sure how true or whether he was just trying to sell me his hideously expensive braizing stuff. I just ended up using push fit brass fittings since the compression fittings are terrible.
4 bar is standard in farm houses - i've got one and i've been in several others and it's always set to 4 bar. Not a problem when you have a regulator attached to the incoming mains as you can simply turn it down which i've done here.
Not sure about most rural properties having a brouilleur with the burner, i've seen one in the more than 200 farm houses i've been in. Most people have a burner with no boiler or electric rads.
That said, you definitely can have a header tank set up. It's things like electric showers that aren't allowed and lots of expats try to bring them with them. I nearly did until i realised my pressure + a water heater does the job better than any shower i've ever had.
