Hello.

For example that I managed to get myself legitimized as father of child.

Mother skips town and disapears to Europe.

I carry on with judgement through the Thai courts and they legitimize me and grant shared custody would this judgement be recognised in European countiris?

Yes, it would be recognized there. Also a court order giving you shared custody will, although they might convert it to a local variant and there could be an investigation by local social services.

Thanks Mario - I am talking France specifcly

Can't give specific information about France. In general they will recognise a Thai court decision. In case you have shared custody before she moves there, I suspect the mother will need your approval to get a visa for her child for France. If you get it after, you can get visitation rights enforced in france. But like I said, that will likely go through the French social services.

France is a member of the Eorppean Convention on Human rights and party to the treaty of the rights of the child. They will handle the case in the best intrest of the child, which normally is that the child should have contact with both parents. The question migt be more how practical it will be for you to really see your child in France.

OP, you don't ask so maybe this is not an option / important

If the mother abandons the child, then you should request sole custody and nothing else. You will be in a better position getting access to your child in Frace if a Thai court has granted you sole custody

"For example that I managed to get myself legitimized as father of child" - This doesn't sound right. You WILL get legitimized and you WILL get shared custody in a Thai court, unless something is very wrong