Change sizes on my product page using custom code

Site URL: https://www.lerligisa.com

Hi, 

I have added a third-party on my website "We Glot" to translate my English website into French. On my product page, when I select sizes, they automatically appear as US sizes (2, 4, 6...). On the French version of the website, I would like the sizes to appear as French sizes (36, 38, 40...). Is there any way to do that using a custom code? 

Thanks, 

Eva