"These are my car keys, did you take them from my pocket?"
Translation:Ce sont mes clés de voiture, tu les as prises dans ma poche ?
This keeps catching me out:
•When the auxiliary verb is être, the past participle must agree with the subject •When the auxiliary verb is avoir, the past participle may have to agree with its direct object
Your answer is in the comment above by gdlh :) When the direct object comes before the past participle, then the past participle will agree in gender and number with the direct object. In this case 'les' (meaning les clés which is feminine plural) comes before, to make the past participle 'prises' (feminine plural)