Boulanger, deux

I have been knee deep in French googling. The Argus online has just in the last day put 1861 on which enabled me to find an death notice for an Auguste Gréterin, Director-General of Customs of France who had just died. He was "first Cousin to Mr. Boulanger of this city" (Melbourne. He was living in Williams Rd. at that stage). Calloo-callay! The man in question wasn't registered as Auguste but Théodore Gréterin (1792-1861 and a Senator with a bit of bling) who had three brothers (Phillipe, Pierre-Dieudonné and another unidentified) all of whom were in customs. The important bit was the revelation of his parents: Evrard Gréterin and Jeanne Nicole Hanus (1765-1833). All of which means that Edouard Boualnger's father Antonio had married either a Géterin or a Hanus. Well, there's a maiden name. Evrard is a variant of Edward, used in Nordic countries and Belgium (Walloon). I'd bet a guinea to a goose that Edoaurd was named after his mother's brother Evrard (or the father if Evrard was a Jnr.)

Now, I have to find Antonio Boulanger's link to the Duc de Montebello.