Errrr, oh!
BH 28
12 11 10 9 8 7 6 5 4 3 2 1
R R 17 16 15 14 13
28 27 26 25 24 23 22 21 20 19 18 R R R
BH12
40 39 38 37 36 35 34 33 32 31 30 29
Yes, it's upside-down

I've heard of this, although I've not seen it before, nor do I know if it's some cars or all of them.
Using the above and this
http://www.peugeotlogic.com/fuses/fuses406/fuses9.htm it looks like the fuse position for the lighter is empty (looking at the 2nd row from the bottom, left to right, free, 5A (fuse 27), free, 20A (fuse 25), free, fag lighter (should be 20A), 10A (fuse 22), free, free, 30A (fuse 19, should be 10A), 10A (fuse 18) and the last three are reserve fuses.)
It all seems to match fairly closely anyway. Stick a fuse in 23 (a or b) and see what happens.