This paper presents the demonstration of TENET, a generic and open source tool for building OWL ontologies from texts written in natural language. We illustrate the different steps of the processing chain, including: Going through a pivot semantic representation of the utterances (serialized in RDF), as well as setting up and performing the extraction and construction process of the target ontology. Finally, we show how the target ontology can be exploited, in an industrial context, with an example of automatic verification of system requirements.