The five-eighth was fined after pleading guilty to charges of common assault and resisting arrest for an incident that occurred at a Jersey nightclub last month.
Cipriani was selected for Gloucester's first Premiership game of the season and delivered an exquisite pass over two Northampton players to Charlie Sharples, who crossed for one of his team's two tries.
James Hanson had gone over earlier after a driving maul from a lineout and though Piers Francis and Courtney Lawes scored tries for Northampton, 17 points from Billy Twelvetrees's boot meant the hosts started their campaign with a victory.
Last year's beaten finalist Exeter Chiefs made a statement by thrashing Leicester Tigers 40-6 at Sandy Park.
The Chiefs, who finished the regular season at the top of the table last term, scored 26 unanswered points in the second half against a Tigers team that only managed two early George Ford penalties.
Olly Woodburn and Sam Simmonds both burrowed in from close range in the first half for Exeter, while Luke Cowan-Dickie, Henry Slade, Matt Kvesic and Ian Whitten all crossed after the break.
Harlequins also ran up the points in a 51-23 rout of Sale Sharks, which was stunned by a second-half blitz too.
Ben Tapuai's second try on the stroke of half-time nudged Quins 24-20 ahead at the interval and the Sharks added just a penalty after the break while Joe Marchant, Marcus Smith and Max Crumpton all dotted down.
Billy Searle's penalty 12 minutes from time earned Wasps a 21-20 success over Worcester Warriors.
Wasps, which lost Cipriani to Gloucester and were without Jimmy Gopperth with injury, while Lima Sopoaga was not deemed ready for his debut, handed Searle kicking duties and he was on target with a crucial late three-pointer, though Worcester came close in the dying moments with a drop-goal attempt from Duncan Weir.