mDNS discovery in openHAB2 not finding my service type

I need help with mDNS discovery in openHAB2.
I try to implement a mDNS discovery service for the Freebox server but it does not work.

Here is the result of avahi-browser on the same RPI 2 that runs OH2:

avahi-browse --all
+   eth0 IPv4 Freebox Server                                _fbx-api._tcp        local

Here is the log entry when I start OH2 inside Eclipse IDE:

2016-05-11 15:35:54.849 [DEBUG] [s.i.t.m.d.MDNSDiscoveryService:88   ] - 0 services found for _fbx-api._tcp

What’s wrong ?