What are the main difference in ingredients between French bread and white sandwich 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.
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.