OK , I can’t speak for other countries but I can certainly give a bit of guidance on what to buy in France and what you might want to bring over from the UK for your renovation/restoration project.
Let’s start by debunking a persistent myth; that French paint is poorer quality and there is less in every tin. This may have been true years ago but I can safely say the contemporary French paint ranges are fine. You can buy brands such as Dulux in most “retail park” type DIY superstores but it is more expensive here in France.
What is a problem is finding specialist period or heritage shades outside the major cities. These haven’t quite hit La France Profonde yet. If you want these, bring them with you
We have experimented extensively, to the point that we can construct impromptu coffee tables, but to save you the trouble and expense of this we present our best find- a trade white “1er” emulsion with great coverage at a tiny price (under 15 euros for 10 litres) from Mr.Bricolage chain
Be brave (I am) and I have mixed up some great shades; just keep a jar for touch ups! http://www.mr-bricolage.fr/
Quality wood & metal paint is easily available, reasonably priced and in some great colours. Some products are specifically made to resist strong sun fade and damage, a big problem in the South here, such as “lasure” which sinks into the wood for a tough matte finish and out-performs varnish in my opinion
Wood treatments and finishes are competitively and comparatively priced and you will find virtually everything you might want, even specialist antiquing and limewaxing products such as the excellent French brand Liberon.