The young French striker left Parma for Inter last week.
Dubroca coached Bonny in Chateroux's youth team and told Tuttosport: "His arrival at Inter is certainly an important step, further step in his career, which will now take a new direction.
"He performed well and made a name for himself at Parma, and it was a given that he could aspire to a place at a top-tier club.
"A potential starter in Milan? He has the potential, determination, and personality to become a top player, but it will certainly take time. Could Bonny really be the new (Marcus) Thuram? He simply has to be Bonny. Of course, I hope he can reach Thuram's level; he certainly has the ability."
The Nerazzurri paid €25m for him and Dubroca added: "It's a very significant fee, but we know the market, and given his age and potential, Inter have certainly made an excellent move. Let me add one thing: Yoan has always maintained his positive mentality. It's always a pleasure to interact with him; he's a guy who doesn't forget where he comes from. I wish him every success in this new project."