Éléonore de Grandmaison has 3 husbands who are not questionable, the evidence is there. However, her purported first husband appears to be an error on a marriage contract of hers in 1652. I found the original contract, which names Antoine Boudier sieur de Beauregard as being her deceased husband. BUT, and this is a big but, her husband François de Chavigny, whose children have provision made for them in this contract, is NOT listed as her deceased husband.
Would need a second look at the contract to make sure I have not missed something, anybody who is good reading old French records, could you please take a look? Original contract linked on profile, it's her 1652 marriage to Jacques Gourdeau.
Everybody and his successor (sources) have all repeated that she was first married to Antoine Boudier sieur de Beauregard (starting with Tanguay), but this contract is the only place where he is named. He certainly never came to the colony. Seems like an error by the notary to me.