Can I bequeath home to partner then to be split between grandsons afterwards?

Can we stipulate in our wills that our French house is to be sold on the death of the surviving spouse and the money split between our two grandsons? Hopefully this will alleviate the tax they will have to pay. 

Such an arrangement is acceptable in the UK, however, such instructions will not necessarily bind the heirs/legatees with regard to French property as there is no such thing as a ‘trust for sale’ (as this would probably be seen in the UK) in French law.

It will certainly not alleviate tax and will in fact be irrelevant to the calculation and payment of duty (although this can in certain circumstances be deferred pending sale if the estate has no other available cash assets – this must be referred to the notaire).

A French will opting for English law cannot create a trust as French law specifically prohibits the use of trusts for succession purposes, and I believe an attempt to do so would probably invalidate the will on grounds of public policy.

Depending on your circumstances and exactly what you seek to achieve, it might be useful to talk to a notaire about organising a pacte de famille in which, for example any living children you have could agree to waive their inheritance in favour of the grandchildren.