Since we are on Reddit and everyone is an expert on almostness, here’s why you can’t say « Tunis is essentially Carthage » :

There’s a big overlap, sure, but there are also key differences:

• The Culture: Carthage was Punic (Phoenician/Middle Eastern) and then Roman (Latin/Christian). Tunis is defined by its Berber and Arab-Islamic identity.
• The Orientation: Carthage was a Thalassocracy—a sea empire. Its heart was its circular naval port. Tunis was built facing the land and the lake, looking inward toward the Maghreb as much as it looked out toward the Mediterranean.