Paris, Metro station Châtelet, Thursday noon.

Approaching line 4, you start to hear airs of Brahms, Vivaldi or Mozart. The vibrations through the tiled corridors give the impression that you've stumbled into a grand concert hall. Around the next corner, there's the orchestra.

The modest venue is misleading. Prélude de Paris is a professional orchestra, having made European and African tours and appeared on several radio and television programs.

Still the orchestra performs here every Tuesday and Thursday afternoon. The price of admission is only the cost of your metro ticket and whatever change is leftover from your last coffee of the morning. You can also buy a CD and take the memory home with you.