Citroen C3 Pluriel roof not fully open?

My Citroen C3 Pluriel roof refuses to open more than 4-5".
Then it makes a cracracra noise before it closes back.
During the same period, the boot does not open at all.
Is that because a sensor thinks that the roof is open although it's not?
Btw, the problems started during some weeks when my battery was almost empty (I had to start downhill), but it continued with the new battery too.