We could go on and on about which wine to drink with foie gras, but at the risk of sounding like a provocateur, I don't think Sauternes is the right choice. In my humble opinion, with foie gras, which is already very smooth and creamy, a very sweet wine like Sauternes that matches this smoothness is not great.
Instead, I suggest you try a very dry white wine to contrast and bring out the taste of the foie gras, for example a white cote du jura (the one from
domaine Rolet in Arbois is excellent).
If you're still keen on a sweet wine, then try something more nuanced, like a Coteaux du Layon "Croix blanche" (
Sylvie Termeau's in Rochefort/Loire is perfect).