What are the main difference in ingredients between French bread and white sandwich bread?
French bread has a crispy crust and a soft, airy crumb inside. White pullman bread often has a fat or eggs as a component and is a more dense crumb. French bread is shaped by hand and white bread is often a loaf made bread.
French bread uses hard wheat flour, aka bread flour. And most French bread recipes do not contain egg and a bit more salt to retard the yeast rise just a little. The rest is technique.