Pondicherry is the capital city of the Indian union territory of Puducherry. City holds connections to Rome, Dutch, Portuguese, British and French right from 1st century. City was part of the Pallava Kingdom in the 4th century. Cholas took control between 10th to 13th centuries, then the Pandyas and finally Vijayanagar Empire took control all of South of India in the 14th century. Bijapur Sultan’s took over from 1638.
The French East India Company established in this town as their headquarters in 1674. It changed hands between the French and British on several occasions, finally French continued to hold it till 1954 when it was incorporated into the Indian Union along with the rest of French India.
Basically its a small city, which looks very foreign to Indian eyes. You can very well compare it to Goa. There are lot of foreigners still continue live just like the regular Indians here.
Overall worth spending day or two, you will be able to cover all places. If you have time I strongly recommend visiting Mahabalipuram which is just about 100 kms from here, I guarantee you wont regret it.
Let me know if you have traveled here or any questions on the same.