According to the card, the patch is not recommended for children under 2. The card names no special rules of use for older children. Other warnings: do not use in case of allergy to eucalyptus oil and camphor, do not use in case of asthma; if the sticker is swallowed, seek medical help immediately; keep out of the reach of children.
General information (not a manufacturer's instruction): a patch with camphor and essential oils is better used for children only after a paediatrician's advice.