Finely dice the green onions and garlic. Drizzle a large pan with olive oil and saute onions and garlic for 1-2 minutes, until garlic is soft and fragrant. Remove from heat and set aside.
In the a medium mixing bowl, stir together the cream cheese, butter and mayonnaise. Mix in Parmesan cheese, garlic powder, salt and pepper.
Pour in the onion and garlic mixture and stir together with the cheese mixture.
Slice the french bread in half lengthwise and spread the cut sides of the bread with the mixture.
Bake for 5-10 minutes, until the topping has warmed through and the bread is golden at the edges.