After the two chairs of tovdesign and some rights reserved I found a third example of a chair made of recycled/reused cardboard.
Daniel Duarte is a student of Interior and Equipment Design at the School of Applied Arts in Castelo Branco.

“Despite the complexity and limitations in achieving this seat, everything was framed in one way or another, giving rise to a Windsor chair with no support for arms, relaxed and comfortable-looking, strong supporting a maximum weight up to 250 kg.” (Translation via Google)

I think the result is very successful. Daniel Duarte did a great job and a very nice thing, he offers the manual at his page for free: