Sang
Cela fait faire du mauvais sang = That causes one to worry.
Suer sang et eau (fam.) = To strain every nerve.
*Bon sang ne peut mentir = Good breeding always shows itself; Like father, like son.
Sapin
Sa toux sent le sapin = He has a churchyard cough.
[Sapin = deal, of which coffins are made.]
Sauce
On ne sait à quelle sauce le mettre = There is no knowing what to do with him.
*Trop de cuisiniers gâtent la sauce = Too many cooks spoil the broth.