You're right a real weapon, not only for show.
Here's a picture of a Ngombe warrior with sickle knife and shield
A sickle knife from my collection. It still has a leather strap attached to the handle. Length : 81 cm ! The handle only measures 9 cm. The blade is completely engraved on one side. The other side is almost plain. There's only a small engraving where near the small moon shaped extension.
Look at the very nice engraving.
Still a very functional piece. The blade is sharp on both sides and on its full length.
Now it's up to you again, Tim