non-entry
a feudal casualty. This was the rents from a dead vassal's property which fell due to his superior until the vassal's heir was entered with the superior
I'd plump for non-entry rathe rthan non-entre.
I think the 'in France' bit probably just refers to the 'no' and then comes ENTRY (way in)
I think teh clue shoudl say vassal's heir as per Mamyalynne's link