It's possible that:
* The name is spelled differently: Perhaps there's a slight variation in the spelling.
* The person is not well-known: If they're a less famous actor, their projects may not be widely documented online.
* They are not an actor: It's possible Franz Marx is involved in another field, like directing, producing, or writing.
Could you please provide more context or details about Franz Marx? This will help me provide more accurate information. For instance:
* Do you have a specific film or TV show in mind where you think he might have been involved?
* Do you know anything about their profession or what they do?
The more information you provide, the better chance I have of finding the answer you are looking for.