Nice is a large city in France, and the Ferraj corner is where the wealthy of Nice congregate. When a fire breaks out in such a place, it's impossible for the fire department to arrive late.
As for the gunshots, would anyone investigate if no one reported them?
The answer, of course, was no.
In fact, when the rabbit fired that shot, it didn't make much sound from the outside, and it was the only shot fired from beginning to end. Moreover, although Deyo's bodyguards rushed out quickly, by the time they realized the shooter had already run away, they retreated just as quickly.
So, the only trouble might have come from those two explosions, but isn't using a natural gas explosion as the cause of the fire perfectly suitable?
For Deyo's people, retaliation was never the first priority; managing the aftermath was what mattered most.
Moreover, Yang Yi didn't believe that Deyo would dare to live in Nice if he didn't have some sort of relationship with the French government.