Where was Les Petits Meurtres d'Agatha Christie filmed?
French TV series
Les Petits Meurtres d'Agatha Christie (2009–) was filmed in Douai, Armentières, Villa Cavrois and Antoing Castle, 4 places named in its French Wikipedia’s Tournage section, in France, Belgium. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Places per French Wikipedia's Tournage section
French Wikipedia’s Tournage section names 4 places. Each links to the sentence that says so.

