Refund of tax paid on pension lump sum, french resident

I need some help regarding the tax I paid on a recent UK pension lump sum I took, I have been a french resident for 20 years and pay my tax in France. so I will be paying tax on the pension lump sum here in France. How do i get a refund of the tax I paid to the UK,

Hi CB24300 Dodson,
Not all pensions are tax free in the UK. please refer to Tax on your UK income if you live abroad to see if yours is exempt and if so complete the double taxation relief form.
Thank you.