Seems to be based on OpenStack [1] Storage [2].
That means any client that supports OpenStack (and Rackspace Cloud Files [3], for that matter) like Cyberduck [4] and a lot more should already be compatible with hubiC.
[1] http://mir7.ovh.net/ovh-applications/hubic/hubiC-Linux/1.1.1...
First I tried to use API console to get storage API URI and auth token, but I misunderstood something and it didn't work for me.
This, on the other hand, helped, although it uses some other API endpoints (still, those are OVH APIs): https://github.com/gierschv/node-hubic-swiftauth