Continuity mistake: When Joan first meets with her captains in Orleans, they argue. She walks away and La Hire calls her "a helluva woman". As she walks away, you can see him looking at her. Immediately, she turns back, and he is now looking at the other captains as she walks up to him and belts him. He must have turned his head very quickly, too quickly to be caught on film.
Continuity mistake: When young Joan is lying in the field and finds the sword, she points the sword towards the sky, and the side handles are vertical with her body. Then in the aerial shot going toward her, this time and throughout the rest of the small part, the side handles are horizontal with her body.
Continuity mistake: After the 2nd battle (when Joan got an arrow in the chest) she wakes up her soldiers the next morning and uses the tower to break down the English bridge. At the bottom of the bridge when its falling (inside the fort), no one is near the bridge when it's falling except the guy who bad-mouthed Joan earlier that morning. Then in another shot there are at least eight guys getting crushed by the bridge.
Continuity mistake: When Joan has the arrow in her chest, she rips it out and blood splatters everywhere. In one shot its all on the right side of her face, some dry and some droplets of blood on her cheek. Yet when the medic comes after she's fallen asleep, he kneels down to check if her hearts beating, but there is only a tiny tickle of blood on her cheek, then a closer shot appears with blotches of blood - dry and wet - on her face.
Continuity mistake: After the English surrendered and turned around, the king is talking about how his armor is to tight and someone is trying to cut his hair. Watch the barber's thumb, it moves from being on the back of the scissors handle to across between shots.
Continuity mistake: When Joan uses the huge tower to knock down the bridge, you can see a plank of the bridge get knocked off when the tower hits. However when you see the bridge fall down from the inside, the plank is still on.
Factual error: Early in the movie, the Dauphin receives another letter from Joan (or her writer). The only person who ever wrote to the Dauphin about Joan was Robert du Baudricourt, and he wrote one letter, and it was about Joan, not for her.
Plot hole: Joan of Arc is called to save Orléans from the siege of the English. But if you look In the scene where we see a bird's eye view of the city, you will notice that there are no guards on its walls. A siege is the means enemy soldiers try to cut a city from its supplies and contacts. Those soldiers should be guarding it day and night, and sometimes even shooting arrows or rocks in it, until the city resigns. The siege we see at Orléans is nothing but a lonely catapult which shoots once a week.