First of all if they paid the fine especially the full 10,000 Euro, then they are either repeat offenders or they were very disrespectful to the authorities.
And there is no way the Captain will be forced to pay the fine by the courts. The company is untimely responsible for their aircraft on the LOA's etc as well as financially responsible... Does the Captain have to pay the FBO if the company doesn't? I think not!
Sure they can punish the Captain internally, not monetary I am sure. Even a firing of the captain would be difficult, if he didn't want to leave. All the Captain has to say it was a safety of flight issue and no one can do anything.
Good luck getting blood from a turnip!!!!
j