Capital Gains Tax on Overseas stock portfolio sale

Hello, I am a UK and French citizen. I have a stock portfolio in France, opened when I was still living there. I may have to sell part of it. There will be Capital Gains Tax payable in France (flat tax rate of 30%). The money will remain in France. Do I need to declare it in the self assessment and pay tax in the UK on this? I also have an Assurance Vie, a tax-efficient French life insurance bond that is used to hold multiple investments. Is that the same for this? Thank you for your help

Hi,
If you are resident in the UK, then under the 'arising basis', you are required to declare your world-wide income and capital gains. This is done through a Self Assessment Tax Return. You will need to review the tax treaty betweent the UK and France in relation to your capital gain.  
If the treaty allows both countries to tax your gain, you can claim a foreign tax credit in the Self Assessment Tax Return, so that you do not pay the same tax twice.  
Please have a look at the helpsheet HS321 regarding foreign life insurance policies.
HS321 Gains on foreign life insurance policies (2024)
Thank you.