In 2009, francophone theatre company Théâtre la Catapulte, whose mandate is to create and produce theatre in Canada’s national capital, staged a site-specific “colingual” performance in which spectators walked between different stage spaces in Ottawa’s central and historical By Market. The components of this performance, le Projet Rideau Project, were six twenty-minute plays, three of which were in French, three in English, by six different authors and directors. The linguistic negotiations at the heart of the project required theatre translators to balance the language dynamics in the context of the performance: four plays in English and two in French at an English-language theatre festival, and the opposite proportion for a French-language festival. Self-declared by its instigators as “colingual,” le Projet Rideau Project showcases the stakes around writing, staging, and translating heterolingual theatre in a context of official bilingualism.