Musée Jacquemart-André audio guide,
five stops, free.

You are in the most private room of the house. Before it held books, this was Nélie Jacquemart's bedroom, and later she and her husband Edouard André came in here to go through auction catalogues and decide what to buy next. Of everything on these walls, the museum calls the little panel in front of you truly priceless. It is thirty-nine centimetres by forty-two. You could carry it under one arm.

The story comes from the Gospel of Luke. After the crucifixion, two disciples on the road to Emmaus fall in with a stranger and ask him to eat with them. At the table they suddenly recognise him as the risen Christ, and then he vanishes from their sight. Painters had shown that supper many times. Rembrandt, around 1628, when he was about twenty-two, found a new way to do it.

Look at the right side of the panel. Christ is there, in the foreground, and you cannot see his face. The light source is hidden behind him, so he becomes a dark profile against a glowing wall, and the light seems to come out of him rather than fall on him. The museum connects the effect to Caravaggio and his followers, chiaroscuro pushed as far as it will go. The daring part is letting the central figure of the story be a shadow.

Now the two disciples. One sits at the table staring at him, lit full in the face, frightened. The other you may miss altogether. He has knocked his chair over and dropped to his knees at Christ's feet, and the dark has almost swallowed him. Then look to the far left, into the back room. A servant is busy by her own small light, getting on with her work. Take the miracle away and this is an ordinary evening at an inn, which is how the museum describes it too.

Rembrandt came back to this subject again and again. The Louvre owns another Supper at Emmaus by him, calm and symmetrical, built around a central axis like a history painting. The museum's verdict is that no other version reached the perfection of this early one.

It came here by a long road. Willem Six owned it in Amsterdam until 1734; after him came collectors in Brussels, Paris and Vienna, until the dealer Charles Sedelmeyer sold it to Edouard André. It was not the first Rembrandt the Andrés owned: Edouard had bought a portrait by him, of a Doctor Tholinx, back in 1865, and this small scene joined it later. In 2019 it travelled to Milan and hung at the Brera beside Caravaggio's own Supper at Emmaus, the painter whose light it had borrowed. Then it came back here, to the room where the Andrés sat reading sale catalogues.

Few people come to the Boulevard Haussmann expecting Bernini, the man his own century thought its greatest artist, who worked in Rome for one pope after another. Yet here he is, in bronze. The man is Pope Gregory the Fifteenth, and the bust is one of the rare seventeenth-century pieces that Nélie Jacquemart ever bought. Her heart was in the Renaissance, but she knew quality when she met it, and in 1899 she bought this at a Stefano Bardini auction in London.

Gregory the Fifteenth was born Alessandro Ludovisi, in Bologna, and he was pope for barely two and a half years, from February 1621 until he died in July 1623. Bernini started a marble portrait of him straight after the election and had it finished by September. Bronze casts followed. The marble is in Toronto now, at the Art Gallery of Ontario. What you are looking at is a cast after it, and for a long time that made it look like a lesser thing. The museum says recent research has turned that round: this may be the very first cast, finished with Bernini's own chisel for an important Roman collector, and it now counts as a major work.

He worked fast because he recycled. The cope, the heavy ceremonial cloak, is borrowed almost whole from a bust he had made in 1618 of the previous pope, Paul the Fifth. He changed the clasp, and he changed the two little figures on either side. Look at them now: Saint Peter on one flank, Saint Paul on the other, the pope's protectors, set into the embroidery. Then look at the head, sunk low into the collar, so the whole bust becomes a triangle. It is a sickly man of sixty-seven, bowed under the weight of his office, with eyes that are still wide awake.

The portrait paid off handsomely. On the thirtieth of June 1621 this pope made Bernini a knight of the Order of Christ, with a salary for life. He was twenty-two. From then on Rome called him Il Cavaliere, the Knight.

Before you move on, look down at the base. Of all the casts of this bust, this is the only one whose socle carries coats of arms.

This is the last room of the Italian Museum, and the one that owes most to Edouard André's own taste. When every collector around him wanted Florence, he wanted Venice and the north of Italy, and the room is full of it: Bellini, Crivelli, Carpaccio. On the left wall as you come in hangs a small, hard painting by Andrea Mantegna.

Ecce Homo means Behold the man. They are Pilate's words as he shows the tortured Christ to the crowd. Mantegna painted this around 1500, late in his life; he died in 1506. Look how close he brings you. Christ fills the canvas, half-length and naked, which the museum points out is extremely unusual for this subject. The whip has marked his body. His wrists are tied, and a rope is looped round his neck and knotted at the front, like a leash. His halo is transparent; you can see straight through it.

Then the faces crowding at his shoulders. Two of the men lay a hand on him to hold him captive. On the right, under an orange turban, an old face with an open mouth, said to be an old woman. On the left, a man whose headdress is covered in writing that looks like Hebrew and is not. Behind them, more faces in the half-dark. The museum says no painter before Mantegna had drawn faces so close to caricature to show rage and the wish to kill, and standing this near, you feel the room go tight.

Now read the two paper labels at the top corners, painted as if they were pinned up. Crucifige eum, tolle eum. Crucify him, take him away.

The colour is almost grisaille, greys and pale flesh worked thinly, so the figures look carved, like ancient sculpture. For a long time that intensity counted against the painting, and people doubted it could be Mantegna at all. It took two exhibitions, one at the Louvre and one at the Metropolitan Museum in New York, before it was accepted as his. It seems to be on its original support, and it carries no varnish, so the surface is close to the one Mantegna left: the rope, the see-through halo and two scraps of painted paper still shouting the same thing.