Answer:
What is seen in the middle of March and April that canβt be seen at the beginning or end of either month?
In Paris but not in France, the thinnest of its siblings.
What is the freedom of birds and the pen of old men?
You can spin, wheel and twist. But this thing can turn without moving.
You use a knife to slice my head. And weep beside me when I am dead.
You use it between your head and your toes, the more it works the thinner it grows.