Very old café near Syntagma Square, just next to Attica Department Store.
A quick internet search took me to a cafe-restaurant called Dionysos Zonar's near Acropolis, but this is a different place; if you are looking for Dionysios, he is not here.
It has been renovated recently and the interior is modern, but there is something old in the air. Don't take me wrong; 'old' not in a bad sense, but something of old Athens, something nostalgic.
Interior is spacious and the smokers' area and the non-smokers' are separated. If the weather is fine, there are also tables al fresco.
The clientel is mostly wealthy Athenians and rich foreign residents; if you are a bourgeois, you will probably feel at ease.
We visited here in March 2009.
I had a filter coffee (€4.80; this and all the prices below were correct in March 2009) which came in an unfamiliar metal devise combining the filter and pot together. The coffee itself was surprisingly good: aromatic, deep and caramel-like bitter sweet. It reminded me that I have not had a decent cup of coffee for such a long time.
Waiter explained to us it was the shop's original blend made from beans imported from Italy and from Nicaragua.
Double portion of Greek coffee (€4.80) was accompanied by traditional glyko tou koutaliou (jammy sweets of fruits/vegetables in sugary syrup) of cherries.
The strawberry tart was rather small for the price (€8.50), but there was no denying that it was freshly made from very good ingredients.
They offer a whole variety of cakes and sandwiches.
At Zonar's, the prices are higher, but the quality is higher as well. You will enjoy, if you can tell the difference.
At the corner of Voukourestiou and Panepistimiou streets