3. No suit, defence or exception founded upon the omission of any formality, even imperative, in any act of a community, municipality, school service centre, school board, of one of their officers or of an assessor, shall prevail, unless the omission has caused actual prejudice or it be of a formality whose omission, according to the provisions of the law, would render null the proceeding from which it was omitted.
1979, c. 72, s. 3; 1991, c. 32, s. 5; 2020, c. 12020, c. 1, s. 309123.