There used to be one London estate agent who made a point of being ruthlessly honest about the houses he was selling. He became very successful! IN France, the seller is obliged to reveal any hidden fault (vices caches) an can be sued if they appear after the purchase.
My daughter has just sold her house in New Zealand, without an agent, at $5,000 over the asking price. She put loads of photos of the house and gardens on Trademe, and invited all the people who wanted to view to come at the same time, when they telephoned. Open House is popular in New Zealand, where the owner disappears and the agent shows people round, but they get a fair number of people who just like looking round other people's houses! She just let them in and left them to wander round. ( I always hated it when the seller stayed with me all the time, pointing out the best features. ) Two people made offers at once.
She has come a long way since her first little house in Chester, which cost £14,000 30 years ago!