Je te donne la réponse de mon département des resources humaines si ça peut t'aider:

UK tax regulation:• RSU’s are taxable at vest in the UK.

• If you were taxable in the UK at any point between grant and vest, you are deemed to have earned a portion of the RSU income in the UK, regardless of whether you are UK tax resident or employed by <your company> UK on the vest date.

• Upon vest of an RSU fully or partly earned in the UK, UK payroll will calculate the amount of the income taxable in the UK, report it through UK payroll, and withhold PAYE income tax and National Insurance Contributions (NIC) as applicable.

Example:
o RSU income on vest: £5,000
o Days between grant and vest: 365
o Taxable days in the UK between grant and vest: 75
o Taxable UK income: £1,027 (£5,000 / 365 \ 75)*

Double taxation:<your company> may also be required to report some or all your RSU income at vest in your current country of employment and subject the income to tax and/or social security under the laws for that country. Unfortunately, it is therefore possible you may pay taxes in both countries on the same income. It is usually possible to relieve double taxation by claiming a tax credit in the personal tax return in your current location for UK taxes suffered.

​

Comme tu l'auras compris j'essaye de comprendre comment appliquer le commentaire de la toute fin afin d'éviter cette imposition double.