"Unknown" or "Inconnue" Collineau de Montaguerre, sometimes just "Collineau de Montaguerre" (with Collineau as first name) is supposed to be the ancestress of many, many French emigrants, usually in New France. She is, usually, the last female ancestor in a line, associated with unknown husbands. Apart from her unusual and strange name, it is fairly unlikely that the wife of an unknown 16th or 17th century man would be known. A simple look at her profile shows how improbable she is, with currently 38 husbands representing the 30+ different emigrant descendants (grandchildren or great-grandchilden) she is supposed to have.
This "Unknown" (Inconnue in French) has puzzled many, and to make a long story short, it was decided that she was probably, initially, someone's code for and end-of-line ancestor, and that this joke propagated. This has already been discussed here and here. I think it's time to decide that she did not exist and officially move her to the Disproven Existence project. This means that all the "unknown" husbands she's connected to will be disconnected and replaced by links in her biography.
She could not have been Collineau (given name) de Montaguerre (family name), because women were not given "Collineau" as a given name (Colinot would be possible for a man, from "Colin", a variant of Nicolas). The family name "de Montaguerre" is rare, if not non-existent (since 1891, there has been one "de Montagère" birth in France, after 1966), which rules out the possibility of several different, unrelated people called "Collineau de Montaguerre".
There is however a real "Collineau de Montaguère" family. This family started after the 1794 marriage of Hippolyte Joseph Collineau and Françoise Charlotte Ollivier, daughter of Joseph Ollivier sieur de la Montaguère. Their son, born Hippolyte Collineau, used the name Collineau de Montaguère later in life, and transmitted it to his descendants. There was no one with the name Collineau de Montaguère (or Montaguerre, for that matter) before 1794.
(edited to correct links)