“You may be right, Luc,” he said. “Perhaps I should stop.” He shrugged. “But when one has made commitments, you know …”

Luc stared at his brother sadly. Whatever he had agreed to with the Dalous, he was going to do. That was clear.

“Listen,” said Luc. “I’m going to tell you a secret. I’ve been worried about you. Do you remember a certain place that we went to years ago? A secret place, under the ground, that nobody knows?”

The cave under Montmartre. Thomas didn’t look pleased to be reminded of the incident.

“What of it?” he said.

“I’ve put provisions in there for you. If ever you need to hide, you could stay in there quite a while.” He might have prepared it for himself, Luc thought, but who should he share it with if not with his brother? “Don’t tell anyone, not the Dalou boys, or any of your friends, or even Édith. If nobody knows, nobody can tell. No one comes by my house, as you know, so I won’t lock the door. But if ever you need it, go there at once.”

“All right,” said Thomas.

Schmid was pleased with his arrangements. The key to a successful operation was simplicity. The object of the mission was to discover if Louise and Corinne were one and the same. Everything, therefore, was subordinate to that.

There were three cars, all full of Gestapo men. In the middle car were three men dressed in the uniform of senior Gestapo officers, one as a general. All three were prisoners, due to be shot. They had been told that if they played their parts well, their lives would be spared. The one dressed as a general looked very like Müller.

There would be some police around, of course, but not too many. This was supposed to be a discreet private visit. And he wished to provide the Resistance men with a tempting target. He didn’t want to put them off. They must be allowed to make the attempt on the man they thought was Müller. If they did, then he knew the identity of Corinne. He would arrest her. And then he would see what she could tell him.

The efforts of the police were entirely secondary. Only after the attempt was made were they allowed to move. If they could catch some Resistance men, that was a bonus.

“Try to take at least one of them alive,” he instructed. “I may be able to identify a corpse,” he told the senior police officer, “but a man we can interrogate is worth a hundred corpses.”

The bait was in the trap. Now all he had to do was see if the bait was taken.

The Théâtre de l’Atelier lay in the section of the city just below the steep slope of the park that led up to the great white basilica of Sacré Coeur upon Montmartre.