Cd ejects itself without playing in my peugot 207

If the disc spins but then ejects, then you might try a laser cleaning CD which is commonly available at electronics retailers.

If it ejects immediately, then there will be no getting around removing the player from the car and opening it up for further diagnostics.

It might be due to a mechanical fault, a faulty laser, or any number of possible problems. They are usually complicated to fix or unfixable so you might consider replacing it