I had to make a donation-partage to my 3 children. My notary prepared the deed but in the end 2 of my children refused to sign it. The notary is asking me to pay his fees under the "imperfect act". What is it about?

Je devais consentir une donation-partage à mes 3 enfants. Mon notaire a préparé l’acte mais finalement 2 de mes enfants ont refusé de le signer. Le notaire me demande de régler ses émoluments au titre de « l’acte imparfait ». De quoi s’agit-il ? 

The imperfect deed is the deed drawn up by the notary in which the signature of at least one of the parties is missing. In this case, the remuneration of the notary (his emolument) is reduced by half (art. R 444-59 of the commercial code).