The main general classification contenders, including defending champion Chris Froome (Sky), all finished in the main peloton.
With his 27th career victory in the race, Cavendish takes the race lead in the Tour for the first time. Kittel is second overall, with Sagan in third.
The day's action was led by an early escape instigated by Paul Voss, Jan Barta (both Bora-Argon 18) and late Tour call-up Leigh Howard (IAM Cycling). The trio were later joined by Alex Howes (Cannondale-Drapac) and Anthony Delaplace (Fortuneo Vital Concept).
Voss attacked the escape to claim the King of the Mountains points on the day's two categorised climbs, Côte d'Avranches and Côte des falaises de Champeaux. He earned the polka-dot jersey for his trouble.
With his climbing effort done, Voss dropped back to the break and was later the first to drop out and rejoin the peloton.
Although the forecast rain did not materialise, a cross-tailwind did whip up the speed of the peloton. It was a quickening of the pace with around 80km to go that saw a crash result in Alberto Contador (Tinkoff) falling heavily. The Spanish contender sustained surface grazing to his right shoulder and required medical attention. Luke Rowe (Sky) and Brent Bookwalter (BMC) were also brought down.
Geraint Thomas (Sky) suffered a puncture shortly after Contador's crash, and was part of the group that successfully chased back on.
The peloton slowed to allow the dropped riders to regain contact, giving the break a second chance. However, the day's efforts began to show and only Howes and Delaplace were left inside the final 30km with an advantage of less than a minute. The lead pair shook hands with 5km to go, their day out front over.
The organisation of the sprinters' teams largely fell apart during the final couple of kilometres, with no one team leading the charge. A crash in the finale took down a group of riders, including Geraint Thomas.
Cavendish put himself on the wheel of Sagan in the final half kilometre and then came around him to take the win by a convincing margin.
Due to the crash within the final kilometre, all riders in the peloton when the race hit 3km-to-go were awarded the same time at the finish.
Stage two of the 2016 Tour de France on Sunday takes the riders from Saint Lô to Cherbourg-en-Cotentin on a 183km route with a sting in the tail up the category three climb to the finish line.
Tour de France 2016, stage one: Mont-Saint-Michel to Utah Beach Sainte-Marie-du-Mont, 188km
1. Mark Cavendish (GBr) Dimension Data in 4-14-05
2. Marcel Kittel (Ger) Etixx-QuickStep
3. Peter Sagan (Svk) Tinkoff
4. André Greipel (Ger) Lotto-Soudal
5. Edward Theuns (Bel) Trek-Segafredo
6. Christophe Laporte (Fra) Cofidis
7. Bryan Coquard (Fra) Direct Energie
8. Alexander Kristoff (Nor) Katusha
9. Daniel McLay (GBr) Fortuneo-Vital Concept
10. Greg Henderson (NZl) Lotto-Soudal all same time
25. Chris Froome (GBr) Team Sky
General classification after stage one
1. Mark Cavendish (GBr) Dimension Data
2. Marcel Kittel (Ger) Etixx-QuickStep at 4 secs
3. Peter Sagan (Svk) Tinkoff at 6 secs
4. André Greipel (Ger) Lotto-Soudal at 10 secs
5. Edward Theuns (Bel) Trek-Segafredo at 10 secs
6. Christophe Laporte (Fra) Cofidis at 10 secs
7. Bryan Coquard (Fra) Direct Energie at 10 secs
8. Alexander Kristoff (Nor) Katusha at 10 secs
9. Daniel McLay (GBr) Fortuneo-Vital Concept at 10 secs
10. Greg Henderson (NZl) Lotto-Soudal at 10 secs
25. Chris Froome (GBr) Team Sky
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