I towed a 2013 Ford Fusion Hybrid for several years. It is very similar to the C-max hybrid, has pretty much same drivetrain.
I will echo DouglasC's comments - Ford hybrid vehicles tow great, it worked great for us. Very simple to tow, just basically hitch it up, throw it in neutral and go. I actually kind of miss my Fusion, may well get another one in the future (currently tow a Ford Taurus).
Just a few things to keep in mind about towing a Ford hybrid vehicle:
1. For whatever reason, there is significant draw on the battery when towing these Ford hybrids. Maybe the Cmax is different, but there is a good chance that as part of your wiring, you may have to wire a charge line to the battery. Very simple to do, is a good idea regardless, and will solve this problem completely.
2. With the hybrid Fusion we had, electric power braking is on all the time, and will be on when towing. Meaning, the brake pedal will be easy to push down even when towing with engine off. Not really an issue, and depending on what brake system you chose, it can be really good. Its just something you need to keep in mind when choosing, setting up your supplemental brake system.
Anyway, good luck with it. I think you'll like it. :)