August Braun B. 1839 /Anna Rasal

I'm looking for information on my 2nd Great Grandparents August Braun B. 1839 /Anna Rasal B. 1842. All I know is that he was born in Germany and his Parents were both born in France, a least that is what a census tells us. He immigrated in 1872- 1873 and was in New York for awhile then moved to Minnesota. I would like to find out what his Parents names our since No one in my family has any idea who he is or where he comes from, any help would be grateful. Thank You Robert Allen