Commentaire sur Les Nombres 35:32

ולא תקחו כפר לנוס אל עיר מקלטו AND YE SHALL TAKE NO RANSOM לנוס TO HIS CITY OF REFUGE — The last words are the same as לַנָּס אל עיר מקלטו, "ye shall take no ransom for one who is fled to a city of refuge, i.e., one who has killed inadvertently, cannot be freed from exile by money, by giving a ransom (Sifrei Bamidbar 160:12), לשוב לשבת בארץ THAT HE SHOULD RETURN TO DWELL IN THE LAND before the High Priest dies.

ולא תקחו כופר לנוס אל עיר מקלטו, “and you are not to accept ransom from someone who fled to his city of refuge.” The meaning is that the city elders must not accept a bribe to allow the person who should await the death of the High Priest while still in the city of refuge, and let him return to his hometown prematurely. There was no need for the Torah to warn that one must not settle for a ransom instead of the inadvertent killer taking up residence in the city of refuge. He would not fail to do so because he had to be on guard against avengers of the slain person’s family, his גואל הדם. Not only that, failure to make use of the city of refuge exposes the killer to the suspicion that he killed intentionally.

Like לנס. With a sheva below the [letter] lamed and a kamatz below the [letter] nun [לנס "one who has fled" rather than לנוס "to flee"], meaning that just as there is no redemption for the death penalty, so too there is no redemption for exile.