As well as being one of the busiest weekends in the ‘hectic European music festival calendar’, the second week of August also marks the Perseid meteor shower. Each year at this time - while kids at Oya in Norway or Way Out West in Sweden fasten their wristbands and queue for the bar - the earth passes through a cloud of debris left by the comet Swift-Tuttle. When tiny pieces of dust and ice from this cloud hit the earth’s atmosphere, at around 134,000mph, they burn up to create what we know as ‘shooting stars’, but of course aren’t stars at all.

In France over this weekend, La Route du Rock is held in and around the pretty walled town of St Malo on Brittany’s ‘emerald coast’ where, handily for British music fans, the ferry from Portsmouth arrives. The festival is a chance for a holiday as well as music: nearby are places like seaside village Cancale, renowned for its fresh oysters. The main venue for the festival is Fort de Saint-Pere, an 18th century Vauban castle. During the festival the fort's purpose is inverted - keeping the marauders in rather than out. It fills with sound, some of which floats out into the warm night and the French countryside, la belle campagne, beyond.

There is a more laid back atmosphere than at most British festivals, not quite so drunken. Two jeune hommes performing spontaneous expressive gymnastics at the edge of the crowd are encouraged rather than mocked or bottled. The line-up of La Route Du Rock is united by an otherworldly, empyrean vibe - from dreampop to space rock - as well as the kind of bohemian cool that appeals to the Gallic. A number of the acts even have names on an astral or meteorological theme: Soft Moon, Cloud Nothings, Mazzy Star, former member of Spacemen 3.

Le Vendredi, Alt-J speak fluent French onstage belying the fact they’re from Leeds. They’re clever lads with intricate songs a with a-typical lyrics, such as opener and hit 'Tesselate', occasionally veering into Mighty Boosh’s ‘crumping’. The audience know a lot of the songs, it’s a music-savvy crowd despite the fact that Brittany is primarily known as France's cousin of Cornwall and a tourist destination rather than a hotbed of rock & roll.

Spiritualized (pictured, top) start slowly with songs from cooly received new album Sweet Heart Sweet Light. Jason Pierce, in white and sunglasses, doesn’t look at the audience, making for a heavy space in the middle of the stage. However, the emptiness fills as things build, with Ladies and Gentlemen We Are Floating In Space getting the best reception and final track, old Spacemen 3 Number ‘Take Me to the Other Side’, constructing a crushing crescendo through patient repetition. This is a band in the long game, they know what they are doing.

With no vocal apart from the occasional howl at their lunar namesake, Soft Moon reduce the idea of The Band, or indeed The Festival, to its purest elements: white lights, driving rhythm and primal power along the lines of These New Puritans. It’s hard to tell if this raw or unfinished, slightly lacking.

At this festival, electronic music is out in the open, sous les étoiles, not confined to a ‘dance tent’. Through the impressive sound system, Squarepusher‘s colossal broken beats mimic the monumental architecture of the area: crumbling forts and castellated defence islands around St Malo. Due to the lack of light pollution in rural Bretagne, it is possible to practice casual astronomy at the same time as raving: a mind-blowing combination.

Le Samedi, Savages are the next all-black, new wave-influenced band (after Soft Moon, Chromatics) but are packing sonic impact and well as visual. On record they sound a bit like Clinic but are heavier live, coming over like Public Image Ltd. Camille’s voice has siren element: the singer that Soft Moon needed. Drummer Fay shakes her hands between songs as if on fire and cracks her knuckles. Savages are a proper band, a gang that you want to join: they makes me want to cut my hair off and start playing drums. 'Husbands' is a storming ode to one-night stands and hope: "My house / my bed / my husbands". The band jerk and finish.

The xx

The big draw tonight is the modern crooning of The xx, who after playing some favourites including a slowed-down 'Crystalised' - not too tainted by their favour with TV soundtracks and prime ministerial snuggling - announces that they have “completely finished” their new album and and sweetly ask “would it be ok if we played a couple of new songs?”. The new ones are the same intimate duets but with added Jamie xx electronics and some unfortunate rhymes (“I can see in your eyes / it’s no surprise”). Romy and Olly stand face-to-face battle-wise, their guitars making an x, then another x, while the animated stars onscreen extend into real stars in the sky.

The ‘curated bill’ of La Route Du Rock means that there is usually only one act playing at once so all the audience are united in what we watch. After headliners The xx, stellar soulman and polymath Willis Earl Beal‘s charisma and passion blows away the wishy washy nebulousness of some previous acts. The next night, after Mazzy Star, thousands of people find themselves watching experimental saxophonist Colin Stetson, one of the finest acts of the Festival. Stetson straps on larger and larger saxes, somehow making them instruments produce more than one sound at once, and almost singing though the saxaphone. It’s a physical feat.

There is too much cloud to see many stars or indeed the Perseid meteors tonight but I watch a weird yellow waning crescent moon and the incredibly bright International Space Station passing over; a fast-moving star with humans aboard.

Le Dimanche, to St. Malo to see Jonathan Fitoussi, one of the few French acts on the bill, play on the beach. His ambient chimes, intensifying patterns of bleeps and background of drones à la Brian Eno mingle with the sounds of waves, the screams and splashes of swimmers. On the beach there are a few festival goers (identified not only by wristbands but also unsuitable beachwear: black skinny jeans etc) but mainly tourists and locals. Every year the festival puts on these free beach stage as a thank-you to the people of St Malo - but this rather experimental act makes it subversive, giving the sunny crowded beach a sinister edge. Some people are even oblivious to the loud music creeping, beat-free, into their afternoon.

Chromatics

Later, I am disappointed that Chromatics don’t play their best track 'Tick of the Clock' and finish instead with the limp cover of Neil Young’s 'Into the Black' that inexplicably opens their new album Kill For Love. However, 'Lady' and 'These Streets Will Never Look The Same' from the same record are memorable - a driving soundtrack with ringing New Order guitar line. Repeated vocoder vocal “the screen stayed flashing in my mind” will stay in mine. Johnny Jewel of Glass Candy and facial tattoos provides a needed intensity to the band where singer Ruth walks the line between cool and detached or just a bit weak.

The stage is very dark for Mazzy Star and we can barely see Hope Sandoval. Their dreampop is a model for a lot of other bands on the bill, but they have their own inimitable woozy sound: candlelit heartbreakers, recorded onto tapes for students to snog to. I’ve been keeping a watch on the sky ever since it got dark, tonight there are not so many clouds, and - it almost seems too perfect - during biggest hit 'Fade Into You', I see two meteors shooting across the sky. I thought the lights would raise for the end of the set but no, all that happens is, during the spoken word section on the last song, the audience all move forward as if to hear a whisper in the night.

After the festival is finished I sit out in the deckchair in the garden, wrapped in a blanket, lean back and fill my gaze with sky. Like the Perseids, La Route Du Rock is a special annual occurrence: a chance to think big, think celestial and glimpse some ascending stars before returning to wi-fi and light pollution. Although it is possible to count up to 90 meteors per hour during the shower, I am happy with two more I see - leaving streaks of brilliant light for just a second - before the clouds move to obscure the area of visible stars and the sky is once again completely dark.

Photos by Nicolas Joubard