Tarabiscoville is a fictional city based on Paris, France. This is clearly obvious as seen in some of the books:
In "Les Pyjamasques au zoo", one page shows the Eiffel Tower at the city's bird eye view, confirming that Tarabiscoville is located in Paris.
In "Les Pyjamasques et Roméo Mécano", one page showing slices of cheese that was planned to be cut from the moon that Roméo Mécano intended to sell to the supermarket was marked with signs written in the French language.
Despite the location being based on a French setting, some of the banners and neon lights marked on the city's buildings are written in the English language.
According to "Les Pyjamasques et Utupë, l'esprit de la forêt", it is revealed that the book series breaks the fourth wall as there is one page of the book showing Agent Pin and Agent Pon near a library building containing books of "Les Pyjamasques au zoo" and "Les Pyjamasques et Lilifée" along with a banner saying "Les Pyjamasques" that are seen in an obscure view. This is strongly implied that Tarabiscoville is exactly located where Romuald currently lives in real-life.
Another instance on how Les Pyjamasques breaks the fourth wall is that a skyscraper with a pink neon sign saying "Gallimard" can be seen in one image: