What country was the census taken? If in the US, where? You would also have to search the manifests where a clue might be about where he was born. If in the US, Mateo would have needed citizenship papers perhaps at that time (not sure). Check that out. Did Mateo get married in Italy or US? Look for these records. the name Alphonsine LaFrance sounds French--was she from Louisiana or perhaps New England. Perhaps born in France? If she is on the census, her birthplace would be noted.
Have you checked out : www.familysearch.orgwww.ellisisland.orgwww.abruzzoforum.com
The name Paolini is common and can be found in many parts of Italy, as well as the Island of Corsica (under French rule) and even in South America.