Annual, throughout France, 21st June (the summer solstice in the Northern Hemisphere)
This 24-hour nationwide music festival has grown more and more successful over the last two decades, and is one of the only nights in the year, when under French law, there are no sound restrictions at nighttime. This festival celebrates music in two ways: by encouraging amateur musicians to perform in the streets, and by organizing many free concerts, so all genres of music are accessible to the public.
Launched in France in 1982, Fête de la Musique, or Feast of Music, has become an international event. Because it's fun, because music knows no language or cultural 
barriers and is usually free from politics, because of the huge variety of "events" and participants, and because everyone likes music of some kind. Every year it is celebrated in more than 110 countries worldwide, including the countries of the European Union, Egypt, Syria, Morocco, Cambodia, Vietnam, Malaysia, Congo, Cameroon, Togo, Chile, Nicaragua, and Japan. One could hear the "Ode to Joy" at Berlin's Brandenburg Gate, electronic music on Brussels' Place de la Monnaie, over 200 concerts in the Barcelona streets, musical parades along Athens avenues, "musical lorries" in the streets of Istanbul, concerts in New York City, the Spirit of Music in San Francisco, and much more.
On this day, from sunset till sunrise, musicians take over the streets and play and dance to their heart's content. Musicians of all genres, amateurs or professionals, are invited to perform voluntarily, and the public can strum and hum along. Musicians do not pay to take part, nor is the public expected to pay to watch.
IN FRANCE
Each year more than 800,000 musicians from different parts of the world participate in more than 10,000 concerts. It is estimated that 10 to 12 million visitors travel to France for this event.
Short History:
Christian Dupavillon was a high-ranking civil servant in the French Ministry of Culture. In January 1982, the Director of Music at the Ministry, Maurice Fleuret, sent him a memo saying that the French owned more than four million musical instruments. Three quarters of these instruments lay dusty in cupboards, attics and cellars. The memo spawned a great idea. Why couldn't those cellos, guitars, trombones, kettledrums, triangles and big bass drums wake up, one day a year, find someone to play them and enchant anyone who cared to listen? Why, on that day, couldn't performers, professionals and amateurs alike, play completely freely indoors and out, everywhere, in public squares, under porches and on covered walkways, areas of school playgrounds and hospital gardens, at entrances to churches or music academies or under café awnings, just for the sheer pleasure of playing, freely without feeling self-conscious?
So, they made it happen and the first festival took place on 21st June 1982. It was given the name "Faites de la musique", "Make music”, which in French is a homonym of “Fete de la Musique”, its name today. Since then, it has grown tremendously in popularity.
IN PARIS
One year, we were in Paris for the Fete de la Musique, which happened to be on a Saturday, and the weather was warm and sunny. We were lucky, as many years it’s cloudy or rainy.
In Paris, this is a time when normally reticent Parisians are out late, open to strangers, enjoying their city.
Set-up starts the day before, especially where big stages will be, such as at Parc Champ de Mars by the Eiffel Tower, at Defense, and in front of the Hotel de Ville. I happened on the preparations on Parc Champ de Mars, part of which was blocked off as they were setting up a huge stage. The view from it to the Eiffel Tower was quite spectacular. The next day, half a million people attended the concert here---that must have been crazy. Size of crowds can be a bit overwhelming and rather rowdy in places, so be prepared.
What we saw was much more manageable, mainly around Montmartre---a perfect place for the music fest, as this area is still an artistic and cultural center---and San Michel on the other side of the river Seine.
Early on June 21, we saw many music stages being set up, such as at Place de la Republique. People started to mill around, and traffic to back up, as many streets are blocked off, except to pedestrians. In the evening, all the streets around Pigalle, Abbesses, and Montmartre were thronged with people, lots with kids even though it’s pretty late. Restaurants, bars and cafes are packed to the hilt, but we were squeezed in at restaurant Chez Eugene on Place du Tertre.
That night, more informal dining is also possible: On the streets, edges of squares, or next to the top and bottom of steps people set up tables to sell beers and juice, and prepare hot-dogs or hamburgers---there’s a smell of smoke and of cooking in the air, and you can see the smoke too. Apparently one can’t normally sell/buy at such informal stations, but it seems anything goes this night.
We saw and heard musicians and music of all kinds. It’s noisy, colorful, stimulating. Stop and listen, sing along, dance.
--a group of senior citizens singing Palestrina and Gounod at the bottom of a cul de sac;
--a harmonica player in a porte-cochère;
--a percussion band parading down a street;
--folk music in the underground;
--a young man in black T-shirt and denim shorts near ‘la Consulat’ cafe, playing Paganini on a violin accompanied by a CD in his bag;
--a young couple in operatic dress singing arias outside Sacre Coeur;
--a group of Gospel singers outside Sacre Coeur;
--a group of drummers in the terrace gardens of Sacre Coeur;
---more drummers near Abbesses, all in bright African ethnic clothes.
The metro and trains run extra late that night, until about 4am, and you can buy a really cheap return ticket.
Fete de la Musique: