The amendment reads as follows:
manquement d'ordre militaire est un officier dont le grade est d'au moins un grade inférieur au sien ou il est un militaire du rang;
In French, the word “il” isn't required.
If it is because you absolutely want a pronoun there, that's not required in French, but the beginning of the sentence starts with “la personne”, so it would be “elle”. However, from a French drafting perspective, the word "il" is not required.