what size is a French 36 in a shirt

[StephenDedalus]

What is this in UK sizes? Thanks

It's an 8.

An 8, but a small h&m/zara 8, not a M&S 8

Women’s Numerical French Clothes Sizing:
US size + 32 = French size
UK size + 28 = French size
EU size – 4 = French size
French Sizing Examples:
If you’re a UK size 6, you’re a French size 34.

If you’re a US size 2, you’re a French size 34.
If you’re an EU size 38, you’re a French size 34.

That's from Farfetch

What do you mean 'EU size'? There isn't a consistent one. That's even shown directly by the fact you're comparing France (part of the EU) to some amorphous EU size, where again Italian and German sizing differs. Do you mean the German sizing for EU? That's used also in other neighbouring countries.

If you do mean German, that's not right. The number in the German size should be smaller than the number in the French size.

See this for example: www.sizeguide.net/womens-clothing-sizes-international-conversion-chart.html

I cut and pasted it @Precipice , and I named my source.

Lots of clothes have labels that list US, UK and EU sizes.

It’s a true size 8. Not vanity sizing size 8.

Size 8. I'm a 🇬🇧 14 and take a 🇫🇷 42.