Royal Cat Nap

In a large castle, a king is snoring away. The two Mouseketeers, Jerry and Tuffy, enter the scene. Tuffy has some difficulty climbing onto the king's nightstand, and falls. When Jerry peers over the edge to look for him, Tuffy suddenly appears right behind Jerry. Tuffy starts speaking French, trying to explain himself, then interjects in English, "And I hurt my head, too!" Jerry shushes him.Jerry runs to a nearby piece of cheese and cuts a piece out of it. Tuffy goes for some grapes, but has difficulty pulling a grape off the vine with his rapier. He struggles with it until it comes off, flies through the air, and lands in the mouth of the snoring king, who begins to suffocate. Jerry quickly runs over and tilts the king's head, allowing him to swallow the grape. The two turn to flee, but Tuffy accidentally smashes a tea cup in the process. The king bolts wide awake, and manages to catch sight of the two before they flee.The king is temperamental, and calls for a cat. Tom immediately enters. The king warns him that his sleep is not to be disturbed by any sound, or else he will have Tom beheaded. The mice, who overhear this, decide to make the most of the situation. The king then goes back to sleep, while Tom stands guard. It does not take long before he notices Jerry eating a piece of cheese. Tom threatens him with his rapier, but Jerry simply points to Tuffy, who hurls a vase off the nightstand. Tom runs for the vase and manages to catch it on his rapier. However, the two Mouseketeers are not finished; they proceed to throw every sort of breakable object they can off the nightstand. Incredibly, Tom manages to catch every single one using nearly all his available appendages. Using his only free limb-- his left leg-- he manages to slip outside and drop all the objects, which shatter.Tom runs back into the castle, but Jerry has used the time to sprinkle tacks on the floor. Tom runs in and steps on the tacks. He begins to scream, but quickly stops himself, so as not to wake up the king. He gets outside and proceeds to howl in pain. He pulls the tacks out of his foot and runs back inside. This time, he takes a piece of armour from a nearby suit and uses it to walk across the floor. However, Jerry is ready for him, and stabs Tom in the nose with his rapier. Tom quickly runs over to the king, and plugs his ears so that he will not hear his screaming. At that moment, he finds a pair of champagne corks on the table nearby.Jerry has gotten into the suit of armour, and is making it dance using strings, clanging and clunking loudly. However, Tom quickly points out he has used the corks to plug the king's ears, and proceeds to attack Jerry with his rapier, tearing the suit of armour apart. Meanwhile, Tuffy runs over to the king and uses clothespins to plug up his nose and mouth. Tom manages to spear Jerry by his clothing, but Jerry is quick to point out the king; his breathing having been obstructed, the clothespins and corks fly out of his ears and off his face. He begins to wake up, but a quick-thinking Tom lulls him back to sleep by playing a lullaby on a violin.With that, Jerry and Tuffy flee the room. Tom locks all the doors leading into the room, and swallows the key. However, the mice manage to shoot an arrow through the keyhole of one of the doors, which hits Tom in the rear. He attempts to run outside to let his agonized yelp out, but having locked the doors he cannot. He shrugs, and howls in pain, while the two mice watch from under the door in glee. The king immediately is jolted awake, and proceeds to castigate Tom, vowing to behead him. The two mice exchange glances, feeling rather remorseful. But Tuffy gets an idea; he squeezes under the door, climbs onto the king's shoulder and starts gently singing "Frère Jacques" in his ear. This makes the king grow more and more pacified, until he falls back to sleep. Tom quietly tucks him in.The two Mouseketeers and Tom quietly tiptoe out of the room together and close the door. Tom shakes hands with Jerry in gratitude, and the three then pull out their rapiers and begin battling. In the middle of the fight, Tuffy turns to the audience and quips, "C'est la guerre!" Fade out.

Question: What does tuffy sing to the king to put him back to sleep?
Answer: Frre Jacques