1811 5 Francs Unsure of Authenticity

I have recently started collecting coins again after a 5 year hiatus. I am unsure of the authenticity of this coin as there is a small bump under Napoleon I nose. I am wondering if this is possibly a mark left by a casting process.

Details
   Weight: around 25 grams (sorry its not more accurate, I don't have a good set of scales)
   Diameter: around 3.5 - 3.6cm (was a manual measurement so its not exact)

Hi,

  I think this coin is genuine. i don't see any signs of casting. Could you please post a picture of the edge just to be sure?

I tried to include the entire inscription on the edge.

The part that is worrying me is the spot just below Napoleon I nose, Its hard to make out in the photo but the spot protrudes slightly from the surface of the coin.

The Edge looks good to me. Do you see any dent on the reverse? Maybe someone tried to make a hole?

There is no dent of the reverse.

The wear is even, it's a real coin

Thank you Kenny and Sujit for your help, its very reassuring.