Answer:
I am a protector. I sit on a bridge. One person can see right through me, while others wonder what I hide. What am I?
I am the key that is the hardest to turn
In Paris but not in France the thinnest of its siblings.
I have no head and a tail I lack but I do have arms and legs and back; I inhabit the palace the tavern the cot 'tis a beggarly residence where I am not. If a monarch were present (I tell you no fable) I still should be placed at the head of the table.
A hole in a pole. Though I fill a hole in white I'm used more by the day and less by the night
I go in hard come out soft. Blow me hard and I’ll make a pop.