'Cost of living' isn't just the price of fruit, methinks.

Electricity and gas are more; car insurance was about the same for me(55yo with more than one car) as the UK , but you need to 'add on' all the add-ons in order to make a like-for-like comparison. Also be aware that NCB has a limit of 50% (not 65%), and you get there after 13 years not three.

As others have noted, wages tend to be lower, and jobs are hard to get; if you need to seek an income, look at the ex-pat community first - there seems to be plenty of folk who move here and prefer to import their own workers.

No car tax, but the autoroutes have huge peage (toll) sections. It costs about 90 euros to get from Calais to Lyon IIRC.

Les Frogs don't have Council Tax, they have tax fonciere (which applies if you own a habitable building) and tax d'habitation, which applies if you actually want to live in it. As a guide, our former 3-bedroomed place in Surrey cost us twice per year in Council Tax what this place (a bit bigger, near Grenoble) does in TF and TH together - and we get our bins emptied just as regularly, the roads are repaired when needed, and those with kids get them educated.

Diesel is currently €1.28 round here, don't know what the UK price or current exchange rate is but diesel is generally cheaper than the UK, petrol about the same.

Jobs done by 'tradespeople' tend to be more expensive and have longer lead times - I guess its affected by the 35 hour working week and the national 'down-tools' psyche which kicks in at noon.

You should be aware that France effectively closes all mondays, and for all of August. Don't expect many places to be open when you want them to be.

All that said, Im having a gas, I lost 11 kilos in the first year I was here, and I wouldn't go back to the UK to live if paid.