Another POSSIBILITY...
1880 Census CD
Census Place: 4th Ward, Assumption, Louisiana
Source: FHL Film 1254447 National Archives Film T9-0447 Page 226C

Name
(First LAST ) Relation Sex Marr Race Age Birthplace

Gustave SIMON Self M W MU 30 LA
Occ: Laborer Fa: LA Mo: LA
Sarah BERNIARD Dau F S MU 16 LA
Occ: At Home Fa: LA Mo: LA
Henry EXCINEAU Other M S B 19 LA
Occ: Laborer Fa: LA Mo: LA

The entire record should be reviewed, however. Mis-spellings abound, as you already know. No other Sara's found so far...in 1880

The Baton Rouge Diocese records lumped all the BERNARD's and BERNIARD's - they made note of the fact.

Don't forget that people moved back and forth across the parish lines. They still do today. The fact that the marriage was recorded in Lafourche parish only means that ONE of the parties was closer to the Lafourche court house at the time of the marriage.

Lynda