Narcissus bulbocodium

Hi, Jbardet, I suspect that your bulbocodium could do with repotting. Leaves but no flowers indcate that they are hungry. Normally I would ay that it is now late to repot as the leaves are already growing but in the light of this problem I would get on and do it.
Take the pot under cover for a few days to let the compost dry out a bit and then knock the bulbs out. There will be a mass of tightly packed bulbs in the pot. Replant a good number back in the pot in new compost and plant the rest in another pot or in the garden. I don't think they will do very well next year but should build up energy to flower nicely the year after. With bulbs like these I think it best to repot them every year just after the leaves have died down.

I have a huge number of them in the garden where they self seed and even though our soil is rich (too rich in places for alpines) the clumps have 'rests' and often flower every other year rather than every time. It does not matter when there are hundreds of them though.