MrCutts:
Does Moulinsart have any control over 'fake' Tintin items?
I'm not certain what you mean - if they "controlled" them, the items wouldn't be fake, they'd be authorized; if they are fake, they obviously aren't "controlled"... ;-)
If you mean, would Moulinsart have the legal right to pursue people who counterfeit Tintin merchandise, the answer is, in all probablility, yes, why wouldn't they?
Whether it is possible, practical, or effective to do so may be another matter, involving the judiciary and police of several countries, the state of international relations between those countries, and what degree of importance all those parties place on the matter.
Moulinsart is a very small operation, not some multinational conglomerate with a huge legal department and an international presence which they can bring to bear: they may be actively pursuing these items, or they may not have the resources to do so. International police might be tracking the baddies as we speak, or they might be of the opinion that getting human trafficking and drug smuggling under control is of greater significance. Who can say?
MrCutts:
Have these companies been authorised by Moulinsart to make these figures?
You'd need to ask Moulinsart, as they are the best placed to give you acurate information.
MrCutts:
Have they tried to stop the figurines from China if they are not official?
Again, only they could tell you.
If you are worried about the authenticity of an item, the easy answer is: don't buy!