[Brilec]

Check which battery is in the fob before buying a replacement. The book says mine is a CR1620, but it's actually a CR2032.

But the display should tell you if the battery is low too according to the book.

I used a small knife blade to remove it. The book talks of a screwdriver in the cutout, but I can see no cutout.
If yours is a keyless one it would be slightly different.

 

[Brilec]

I wonder what Peugeot charge for one of those batteries?
I can get 5 for less than £2.00