this sword (at the very least the blade and the sheath) looks like what in the NL is known as a modified " klewang", note that this klewang is not the weapon from Indonesia but a weapon originating in the NL and which was used in Indonesia by the Dutch troops. Klewangs were used from the late 19th century until the end of the Dutch occupation of Indonesia in the late '50
These weapons, in fact cutlasses, were used for a very long time indeed and the local population of the many parts of Dutch east Indies , got hold of blades and repurposed them and modified often times replacing the original hilt and guard.
The general shape, fuller and the sheath, certainly look like a Dutch Klewang which was modified some time after having been acquired or captured in Indonesia.
something like this ( this one not as heavily modified, in my opinion, as yours)
https://www.militariazone.com/swords...6#.Y9jdgy8w1qs
Read more about this kind of weapon here (where you also find pictures of various degrees of modification of such blade)
http://www.vikingsword.com/vb/showthread.php?t=7375
You will see that your scabbard is certainly one which started its life in the NL and then along with the blade was modified. The hilt too could have started its life in Europe and having been modified many European Swords had sud D hilts which could have been ground to look like this