Other People's Money by Emile Gaboriau

Yes, Mlle. Gilberte had her secret -- a very simple one, though, chaste, like herself, and one of those which, as the old women say, must cause the angels to rejoice.

The spring of that year having been unusually mild, Mme. Favoral and her daughter had taken the habit of going daily to breathe the fresh air in the Place Royale. They took their work with them, crotchet or knitting; so that this salutary exercise did not in any way diminish the earnings of the week. It was during these walks that Mlle. Gilberte had at last noticed a young man, unknown to her, whom she met every day at the same place.