what happens to a dough if i dont add ascorbic acid

Ascorbic acid is considered an oxidizer. From the Lallemand dough conditioners PDF:

Oxidizing agents include natural ascorbic acid and chemicals like potassium bromate. They act on the gluten in flour to increase its strength and produce larger, more-uniform finished products. Potassium bromate works well alone because of its slow action, good oven spring, and high tolerance. Most other oxidizing agents act faster than bromate, requiring a combination of ingredients to control the amount and timing of oxidation.

So without it, you might get a little less spring and volume, but leaving it out isn't going to significantly damage your bread.

North American flours often act like they have ascorbic acid already added. The trick for additional spring and volume that's so useful in Paris may not be so useful in New York.