Did you know that a baby's feet play a vital role in many areas of his development? Posture, balance, motor skills, etc. Many have long thought and still think that since a child's foot is fragile, it must be put on with high shoes, firmly laced to maintain the ankle. Now, if we take time to think more about the principle, it is completely the opposite that we would be supposed to do!
Indeed, leaving the child walking barefoot allows the development of sensitive foot receptors that manage both superficial information (temperature, soil roughness ...) and deep (balance, general posture ...). Thus, the baby will be completely free to discover his motor skills without hindrance, especially if you are inspired by the principles of free motor skills. As many feel the need to protect the baby's feet (and this is normal against the cold and the sun), it is recommended to wear non-slip socks or soft slippers. They offer protection at the foot of the child while leaving them full freedom of movement.
For up to 3 years, the bones of the child's foot have not finished solidifying, so it is important not to compress too much in a shoe too rigid. The sole must be flexible and may be slightly rising, but must not compress the 2 balls of bone on both sides of the ankle.
VERY IMPORTANT: Do not choose shoes with a sole with arch. Indeed, children have visually flat feet until about 4 years old. In reality, the arch is filled by a greasy pad. If you add a sole with arch, you risk to crush the bone arch and artificially cause problems of feet and posture in the future.
To summarize and at any age, the ideal is to leave enough freedom of movement to the foot to work its muscles and its ability to adapt, while providing appropriate protection for each activity.
Source: http://osteopathiemontpellier.fr/comment-chausser-les-bebes/