What preposition do I use with übergeben:
Nach dem ersten Weltkrieg wurde Kamerun an Frankreich übergegeben.
I want to say:
After the first World War Cameroon was handed over to France.
Can the preposition "an" be removed or not?
Very simply: No.
You can sometimes do it, but here that would lead to confusion as to what was given and what was receiving.
In cases where the roles are clear, either by context or their cases, you can in non-formal speak do this.
als Preis wurde Mark Wurst übergeben.
als Preis wurde Wurst an Mark übergeben.
as you can see here: The an completely turns around the meaning.
The preposition "an" is the right one to use, but you could leave it away. The sentence would still have the same meaning. But in most cases you would use it with the preposition.
Is this sentence from you or is it from some old book? It sounds like rather old german. You'd rather say:
Nach dem ersten Weltkrieg wurde Kamerun an Frankreich übergeben.