Au Bonheur des Dames (The Ladies' Delight) by Émile Zola:
Just then, the other ladies were arriving. Mouret had been accompanying them and kept them a minute longer to show them Inspector Jouve, who was still pursuing the pregnant woman and her friend. It was very odd, you couldn’t imagine how many shoplifters were arrested in the lace department. Madame de Boves, as she listened to him, saw herself between two gendarmes, forty-five years old, well-dressed, with a prominent husband; but she felt no pang of conscience, merely thinking that she should have slipped the lace into her sleeve. Jouve, meanwhile, had just decided to arrest the pregnant woman, deciding that he would never catch her in the act and, in any case, suspecting her of filling her pockets with such sleight of the hand that he was deceived by it. But when he took her to one side and searched her, he was embarrassed to find nothing on her, not a kerchief, not a button. The friend had vanished. Suddenly, he understood: the pregnant woman was only there to distract him, it was the friend who was shoplifting.