I don't like bread made without any salt. Low salt is okay and I often use the 50/50 salt/potassium combination sold under various name brands here in the US, but I never leave it out entirely.
I also am not a fan of Tuscan bread, or of a similar type made in Normandy. It just tastes flat to me. I have seen people dip it in olive oil and sprinkle on some coarse salt so if one is aiming for a low salt diet, that ain't the way to go!
I've been baking most of my life (worked in my mom's bakery as a teen and went to Dunwoodie baking school in the mid '50s) and have tried just about every version of bread one can bake at home and in my opinion a little salt is necessary to achieve a good balance in bread.
Citric acid or ascorbic acid give a boost to the yeast and will usually yield a lighter loaf but occasionally can speed up the fermentation so that the dough will overproof and collapse when put into the oven. You have to toe a very fine line when adjusting some recipes and substituting ingredients.