A former Lafayette Parish prosecutor was sentenced Wednesday morning after pleading guilty to tax evasion. Joseph Floyd Johnson will spend the next 18 months in prison and will have to pay back over 179,000 dollars in restitution. If U.S. District Judge Richard Haik had given Johnson the maximum sentence, he would've had to spend five years in prison and pay a $100,000 fine. Prosecutors say Johnson hadn't filed tax returns for calendar years 2003 through 2009, owing nearly $180,000. Johnson worked for the Lafayette Parish DA's Office from 1995 through 2008 and had a private practice in Lafayette.