The manager of the bar and two female bartenders sold balloons filled with nitrous oxide, which induces euphoria and laughter when inhaled, for five euros (USD 6.50) a dose, it said in a statement.
"Police learned that the sale of the product was carried out openly by employees of the establishment as part of their duties under the supervision of the manager, who controlled the activity and kept the money collected from the sale of the product," it said.
Millions of tourists visit the Costa del Sol, famed for its beaches and nightlife, every year and hundreds of thousands of expatriates from northern Europe live on the coastal belt.