Here at my in-laws, aperitifs could be as casual as store-bought nuts and crisps with Coke (JL and his father), Orangina (me) or fruit juice (the MIL); or as elaborate as the MIL's homemade puff pastries, tapenade or duck rillette canapes, with the FIL's homemade walnut wine (me), pastis (JL), wine from his little inventory built over the years (the FIL) and fruit juice (the MIL).
Casual or otherwise, the common denominator being assembly work. It also helps when there is a little collection of trays and platters in the house (husbands, beware!) to hold different shapes, sizes and portions.
But at the very worst, the dessert plate or coffee cup saucer does the job as well -- just like the picture above. It was taken during our time in Cambridge when we had only a set of dinnerware for four people. These appetizers are more American than French, though.