Fantômas by Pierre Souvestre

Four months had passed since Etienne Rambert had been acquitted at the Cahors Assizes, and the world was beginning to forget the Beaulieu tragedy as it had already almost forgotten the mysterious murder of Lord Beltham. Juve alone did not allow his daily occupation to put the two cases out of his mind. True, he had ceased to make any direct enquiries, and gave no sign that he still had any interest in those crimes; but the detective knew very well that in both of them he had to contend with no ordinary murderer and he was content to remain in the shadow, waiting and watching, in seeming inactivity, for some slip which should betray the person or persons who had perpetrated two of the most puzzling murders that he had ever had to deal with.

It was the end of June, and Paris was beginning to empty. But the spring had been late and cold that year, and although it was within a couple of days of July society had lingered on in the capital; luxuriously appointed carriages still swept along the Champs Élysées when the audiences poured out of theatres and concert rooms, and fashionably attired people still thronged the broad pavements and gathered before the brilliantly lighted cafés on the Rond-Point; even at that late hour the Champs Élysées were as animated as in the busiest hours of the day.