“And then cannibalism ensued.”

My guide around the mighty Château Gaillard in Normandy delivered this line with commendable insouciance. To be fair, there was so much violence in his recounting of the history of Richard the Lionheart’s castle up to that point that villagers eating each other while trapped in a dry moat during a siege came as little surprise.

“The castle was strategically important,” he added, “because it blocked the main transport route between Paris and Rouen.” And we looked down from the castle’s lofty limestone promontory to the River Seine – broad and dependable, the second-longest river that flows entirely in France, and a veritable motorway in the Middle Ages.

While today there’s still plenty of river traffic sailing along the Seine, it was the opportunity of cycling alongside it that brought me here. Starting (or finishing) at Notre Dame in Paris, La Seine à Vélo (The Seine Valley by Bike) is a route that follows the river all the way to the Normandy coast, almost exclusively on minor roads, cycleways or paths shared with pedestrians. Next year should see the completion of a 25-mile (40km) greenway from Vernon to Les Andelys (home to Château Gaillard) and on to Saint-Pierre-du-Vauvray, which will make the experience even more tranquil.

The Seine à Vélo’s launch in October 2020 was overshadowed by Covid, so it’s only now that the route is coming into its own. The extremely useful official website (in English and French) breaks down the route into cyclable sections, with small-scale maps and details of things to see. There’s also full gpx mapping, which I confess I didn’t download – but the trail is so well signposted (in both directions) that it was a decision I never lived to regret.

I began in far eastern Normandy. This left me with a satisfying four-day, 170 mile-ride across three départements – Eure, Seine-Maritime and Calvados. I booked the overnight ferry from Newhaven to Dieppe, hopped on a couple of trains to reach Vernon (no cycle reservations needed), and before I knew it I was parking my bike at my first stop: Giverny. There’s little fresh that can be written about Monet’s flower-packed garden. However, I did find myself unexpectedly charmed by the artist’s house – the acid yellow of the dining room made everything seem light and sherbety and cheerful.

Monet and his fellow impressionists were very keen on the Seine. I was continually coming across paintings on info boards placed at the spot where one artist or another had set up an easel. And to be fair, there are plenty of views deserving of capture in oils.

The cycling itself was a breeze. The route sticks as close as possible to the river, so there are few climbs of any note. The banks of the Seine have been dotted with towns and villages since time immemorial, and my daylight hours were spent zipping in and out of little communities often surrounded by farmland or squeezed between the river and a steep, thickly wooded ridge. It makes the trail ideal for an out-of-season break, since you’re seldom far from a cafe should the weather turn inclement.

And it was very inclement in the village of Poses, where I spent a night. Stretched along a thin strip of land between the Seine and three lakes, it was originally a place where boatmen and barge haulers came to take a rest (or repos, hence its name) after braving the dangerous currents created by the islands opposite. Nowadays it’s a picturesque village and the site of the Musée de la Batellerie. I was guided around its gloriously restored tugboat Fauvette, home to an absorbing exhibition of Poses life through the generations.

The next day I found myself diving through the Forêt de Rouvray – a remnant of a once vast forest – and into Rouen, the Seine’s only city between Paris and the sea. Despite being 75 miles inland, this was France’s premier seaport from the 16th to the 19th century. The city’s free, summer-long son et lumière uses as a screen the walls of its immense cathedral, once the tallest building in the world. The show was so impressive that a good crowd of us watched the whole performance despite near constant rain. Almost six centuries earlier, France’s favourite slayer-of-the-English, Joan of Arc, faced rather greater trials in the city, as I learned at the Historial Jeanne d’Arc. The museum cleverly tells her story through a series of filmed vignettes that place visitors in the role of Joan’s judges. (I found her guilty, obvs.)

More off-road pedalling brought me to Sahurs and my first-ever bac, one of several ferries that crisscross the Seine free of charge (I took three during my trip).

At the evocative Jumièges Abbey – “the most beautiful ruin in France”, according to Victor Hugo – La Seine à Vélo splits in two, giving riders a choice of Le Havre or Deauville as a destination. I chose the latter, simply because I’d always liked the name but had never been there.

Having pootled along thus far, I was going to spend a proper day in the saddle – covering 110km. The sun burned away the morning mist as I passed through gentle farmland and hit some proper hills. At Berville-sur-Mer – barely on the estuaire let alone the mer – I had my first view of the English Channel shimmering away beyond the elegant Pont de Normandie, whose cable stays resemble vast sails.

One car-free bowl along the river bank and I was at the much-painted port of Honfleur, a pleasing hugger-mugger of old stone buildings cradling a row of restaurant parasols and a vintage merry-go-round. With so many such towns along the way, there’s an abundance of hostelries and eateries to choose from. My favourites were a modern Bord de Seine gîte whose picture window allowed me a riverside view of swans, cygnets and a lone egret, and the bijou L’Auberge du Moulin restaurant in Vatteville la Rue, where the apples and blackberries in my crumble were “freshly picked from just outside the door”.

At Honfleur the route careers away from the Seine into the département of Calvados. So naturally I dropped into Pont l’Évêque’s Calvados Experience to take in its innovative multimedia tour through the history of the local apple brandy. And the tasting session that followed. This proved so generous that I had to lie down in the sunshine for a calvados-infused doze before carrying on.

At length I rolled into Deauville, a town much beloved of monied Parisians. It was all swish hotels, casinos (well, one big one) and a glitzy film festival – quite the contrast to most of the ride. I left my bike and walked out over the seemingly endless sandy beach to say a fond adieu to the Seine. And made a mental note to try Le Havre next time.

Way to go

Dixe took his own bike, but bikes can be rented in Vernon and dropped off for collection in Deauville or Le Havre via Givernon Rental Station. Ferry tickets supplied by DFDS. Newhaven to Dieppe from £23 single. Single rail ticket from Dieppe to Vernon-Giverny from €19; Deauville to Dieppe from €35.70; sncf-connect.com. For more details including accommodation along the way see La Seine à Vélo. For more details about the region see atout-france.fr