The ministaatje bij Rimini is San Marino.

If you’re solving a puzzle with a 3,6 letter pattern, the answer San Marino fits perfectly: 3 letters in the first word and 6 in the second.

Additional context:

• San Marino is one of the world's oldest republics and is completely enclaved by Italy, near Rimini.

• The name consists of two words, aligning with the (3,6) letter count commonly seen in puzzles.