The more solid your relationship with Florian, the easier this conversation is going to be. But no one said this would be easy!
The first thing to understand is that you're not reaching a decision. The point isn't to reach a decision and share information that's important to your organization. Instead you will act as a Change Agent.
Start by checking yourself, as you prepare for this conversation. Assume in this conversation that Florian is unaware he's doing this and that he has no ill intent. It may be more to do with his comfort level, combined with his own history. Perhaps he's giving these employees the kind of coaching he wanted when he started with your company. You don't know. Your job as a colleague and manager is to approach with no assumptions. Check your assumptions, set them aside and assume he's unaware.
Say to Florian, "I've been approached by people you manage, and I don't mind helping them. But what I've heard from them and what I've observed is that you've fallen into a pattern. I don't think you're aware of it, and may be hurting your team's performance. Would you be willing to hear my perspective?"
"It looks like the demographics of the people getting help is very close to your own. What's your reaction? What's your perspective?"
"When your employees come to me, what do you want me to do? Since it's my responsibility to make sure all employees are successful, I want to make you aware of this."
It's your responsibility to bring it up, but not necessarily to engineer a solution or decision out of him. Very likely he is simply naive to the situation, and making him aware will help. But you need to monitor the situation and figure out if and when to go to a higher up for it.
At this point, astute managers could easily take out Eastern European and substitute African American, women, men, Asians and so on. People tend to drift toward their comfort zones and may not even be aware of it. Don't be afraid to check yourself, check with them, and double check throughout the process.