The FDJ.fr sprinter consolidated his lead in the red jersey points competition and proved he was the fastest man in the race after a hectic conclusion to the 173km stage from Modena to Salsomaggiore Terme.
When American Tyler Farrar (Garmin-Sharp) hit the deck ahead of a tight corner inside the final kilometre a whole raft of riders came tumbling down.
Race leader Cadel Evans (BMC) avoided the chaos to finish safely in ninth place and retain his 57-second lead over Rigoberto Uran (Omega Pharma-Quick Step) in the overall standings.
What had been a routine flat ride along the Po River and through the city of Parma became a father feisty affair when two early escapees were swept up inside the final 10km and ahead of a slight climb.
The Sky team of Britain's Ben Swift set a blistering pace up the ascent to cause splits in the peloton, with Bouhanni among those needing to fight back on after a ferocious descent.
Bouhanni and his FDJ team-mates regained contact with 2km remaining and a regular bunch sprint under the leafy trees of Salsomaggiore looked very much on the cards.
But Farrar's inexplicable fall ended the chances for many of the peloton's fast men, including Italy's Elia Viviani (Cannondale) and the Slovenian Luka Mezgec, Giant-Shimano's main man for the sprints following the earlier withdrawal of double stage winner Marcel Kittel.
Sporting a full red skin-suit and red sunglasses, 23-year-old Bouhanni resisted a late surge by Italy's Nizzolo (Trek Factory Racing) while former pink jersey and stage six winner Matthews (Orica-GreenEdge) took third place ahead of another Italian, Roberto Ferrari of Lampre-Merida.
"It was really quick in the end but my team were absolutely perfect. The approach was great and then I did my bit," said Bouhanni after becoming the first Frenchman since Laurent Jalabert in 1999 to win three stages in one Giro.
TWO-MAN GROUP: It was always going to take two sadomasochists to try and defy the peloton on this flat stage and Andrea Fedi (Neri Sottoli) and Marco Bandiera (Androni Giocattoli) fitted the bill - the former having notched up 444km out in front of the peloton ahead of Tuesday's stage, and the latter having been part in three successive breaks prior to Monday's rest day.
Both riding in pursuit of the 'Fuga' prize (for breakaway specialists) and the intermediate sprint prize, the Italian duo quickly built up a lead of almost nine minutes on a fairly relaxed peloton. But their brave effort ended with the obligatory handshake with 9km remaining and ahead of the final rise that shook up the pack.
BIG WINNER OF THE DAY: Nacer Bouhanni's contract discussions with FDJ.fr are getting easier and easier by the day, a third win now making him France's most successful rider this season with eight scalps to his name.
BIG LOSER OF THE DAY: Although he managed to avoid coming down in that final-kilometre pile-up, Cadel Evans lost his first BMC team-mate after Belgian youngster Yannick Eijssen was taken to hospital following an innocuous crash 18km from the finish.
KEY MOMENT: The crash caused by Farrar changed the dynamic of the final sprint - only a dozen or so riders made it through without being held up - but it did not perhaps have any bearing on who ultimately won, with Bouhanni looking very much the fastest man in the race.
TALKING POINT: Can Nacer Bouhanni count himself among the fastest sprinters in professional cycling - or does his success in Italy have more to say about the lack of real competition? On a separate note, is it time for Tyler Farrar to call it a day as a sprinter after yet another painful and unnecessary crash?
COMING UP: Wednesday's 249km stage from Collecchio to Savona is the second longest of the race and includes two Cat.2 climbs bookending a lumpy ride that should encourage a break.
Starting inland and ending on the Mediterranean coast after the punchy Naso di Gatto climb and a fast descent to the finish, it's like a mini Milan-San Remo - but that ascent, which comes inside the final 40km, could well distance the main sprinters in the unlikely event that the break is reeled in.
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- Cadel Evans
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