Hey guys,
So I have two CO2 tanks, 10kg and 2kg, from Germany and I would like to have them filled if possible.

Are there services locally that will fill them, or do you have to have a special license?

For the standard 10kg bottles you can return the empty ones in drinks (e.g. Brasserie Delsart, Beer Wine & Coffee, probably Drink Factory, etc) and they'll give you a filled one for about 25€.

For the 2kg it's not a standard format for beer and therefore you have to have it refilled in shops like fish and aquaculture stores for instance. You usually need to bring it after a night spent in your freezer so that they can load more gaz in. Sadly it actually costs around 15-20€. Jef and Axel have bought connexion to fill their 2kg bottles from the 10kg and it therefore becomes more simple and cheaper to do.

Awesome...Thank you! I have two beers ready to keg next week and totally forgot that I haven't filled my CO2 since we moved here!

To fill the 2 kg with the 10 kg by yourself you need to use a HP CO2 hose