The Central Motorway Police Group (CMPG) said they found the boy on Wednesday night after responding to reports of a pedestrian on the motorway.
"He was split up from his parents a few days ago, and doesn't know which country they're in," the CMPG said in a statement.
"It's impossible to imagine how scared someone would be, not knowing where they are, not knowing where their parents are, unable to speak the language.
"We've taken him to a place of safety with food and water until social services can come and take him to care."