UK Foreign income tax assesment

[Sand]

I am wondering if someone can advise me on foreign commercial use rental income - self assessment with double tax treaty

When declaring foreign income the automatic tax return waver is calculated at 20% - now in France the tax are 20% + 7.5% solidarity tax for non- resident- so my question is when doing the self assessment tax return in UK should we put the full amount of tax paid or 20%?

Or can we add this has an expense as it affect the student Loan calculation?

I am really confused on that one and I am not sure what to advise-

Any idea or web link will be very appreciated



Thank you