notarial fee
notary's fee

While notarial fees may add to the cost of the transaction, they are not a transfer tax in the strict sense of the term.

A small additional payment, as a kind of notarial fee was added (servitia minuta).

Countries with notarial formalities, where notarial fees are set by the value of the subject matter, parties can find that their agreement is subject to prohibitively high notarial costs, which, if they fail to pay, would result in the agreement being unenforceable.