Answer: You say the letter G soft or hard, depends on what you say. Here's why:
The letter G in French is hard when followed by O, A, and U only. It is soft when when followed by E and I. Evidence of this is in the words like garçon, anguille, goût.....and in the conjugation of manger you must add an E back in before the conjugation for nous to avoid that hard G sound.