Final answer:
The question lacks context to definitively state where the beach vacation is being planned. It could potentially be Marseille, as it is the only beach city among the options, but this is pure speculation.
Step-by-step explanation:
The question doesn't provide necessary details about where the beach vacation is being planned. Therefore, we can't definitively say it's in Lyon, Marseille, Paris, or Strasbourg. However, if we consider that Marseille is the only city among these located on the beach, we could infer that the beach vacation may be planned there. However, this is purely speculative and depends on the context provided in the scenario.
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