Encoding error in TopoJSON module

I'm having this error, and I just don't know if it's an issue or something I'm doing wrong. When converting a GeoJSON file, generated by

ogr2ogr -f "GeoJSON" INPUT.json INPUT.shp

with the topojson module, and preserving the properties, some Spanish characters are not preserved:

topojson -p -o OUTPUT.json INPUT.json

For example: Castellón from the INPUT.json file (checked, there are no erros in that file) ends like Castell�n in the OUTPUT.json file. The properties are well preserved except for characters like á, í, ó, etc. (common in Spanish).

I've tried adding --shapefile-encoding utf8 without success.

Well it's almost 1 year late but I'll lleave here my solution because probably more people will have this problem. Solved it in 2 steps:

  1. In the conversion from shp to geojson I encoded it as UTF-8 instead of the standard ISO 8859-1 (I used QGIS for this instead of command line ogr2ogr)
  2. In topojson I added the option --shapefile-encoding utf8 as Nacho did

And all my beautiful accents and tildes are back