Would a longer Maginot Line have helped in 1940?

Would extending Maginot-style defenses toward Calais have helped France in 1940?

Yes. Even lighter fortified belts toward the Channel and Normandy could have provided successive positions and somewhere for retreating forces to regroup.

The counterfactual receives a qualified affirmative answer. It does not require duplicating the heaviest eastern forts everywhere. Successive defensive perimeters toward Calais and south through Normandy, with Brittany outside the main belt, could have slowed an advance and given retreating forces prepared ground on which to regroup. The answer treats fortification as defense in depth and retreat infrastructure rather than as a single supposedly impenetrable wall.