Its quite possible to take a day trip up to Belgium. Many people priorotise Bruges and Brussels, but Ghent is a perfect place to take a day trip from Paris, or even an overnight getaway.
Ghent ("Gent" in Dutch and "Gand" in French for when you are looking for trains) is great for some culture, for food, for the beer that Belgium is famous for, and sightseeing.
What to see
There are quite a lot of things to see in and around Ghent, but the city is compact and easy to get around. This makes it possible to see most of the town in a good days worth of sightseeing. However, you could quite easily fill two days. Especially if you include some time in Brussels or Brugge along with Ghent.
Saint Michael's bridge is a great place to start. It offers great views of the town, the canals and the beautiful Graslei canal-front area. Behind Saint Michael's church is the unfinished Saint Michael's church. Started when the economy was booming in the 15th century but a lack of funds meant it was impossible to ever finish the tower.
Ghent is most famous for its three towers: The Saint Nicholas Church, The Belfry, and the Saint Bavo's Cathedral which stand one after the other on Cataloniestraat and Sint-Baafsplein roads. However, they are best viewed from the St Michael's bridge where you can see the three towers lined up, one after the other.
Not to be missed inside Saint Bavo's cathedral is the magnificent painting by Jan van Eyck: "The Adoration of the Mystic Lamb". It is one of Belguim's greatest artistic masterpieces, as well as one of the most important works of the early Northern Renaissance.
The historic canalfront area of Graslei is a great place to admire the ancient buildings (keep your eye out for the tiny former tax office between the much larger buildings around it). There are many cafe's and bars here to east, drink or recover including one bar that serves over 200 beers just from Belgium. Local Belgian delicacies, such as chocolate, waffles, and the must try purple cone-shaped Cuberdons (they are a must try!).
The Gravensteen Castle (Castle of the Counts), just above where the canal splits at the north end of Graslei is well worth a few hours. The castle was built in the 1100's has was restored in the 1800's. It gives a good insight into the history of Ghen as well as great views over the city.
Ghent, as with other Belgian cities, is crisscrossed with canals -there are numerous operators running canal boat towers which give you a good overview of the city and explain the important buildings, and some of the history of Ghent. Some of these require bookings, some do not - so if you don't want to wait, ask around.
Scattered around the outskirts of the city are the historic beguinage. These are small clusters of buildings in a walled complex, set around a courtyard where in the 12th and 13th century Roman Catholic women who wanted to serve God without retiring from society would live. They are now a much more prestigious address. The Beguinage can only be found in northern France, Belguim and the Netherlands. Several can be found within walking distance from central Ghent.
Wandering around the historic Centrum (historic town centre) is worth the time. There are many great old buildings, now filled with modern shops and some very modern restaurants.
There are a number of great restaurants on Onderbergen (a street on the west side of the river, one block down from Graslel - take the first left after Saint Michael's bridge (after the church) as you are walking away from the three towers). They are a little bit off the tourist track and so are more frequented by locals.
Things to do
How to get there
Getting to Ghent is simple.
Trains leave from Paris, Gare du Nord regularly throughout the day.
The normal and easiest route is to take a Thalys train from Gare du Nord to Brussels where there is a change of train to Ghent/Gand. Thalys is the international high speed train network which travells between Belgium and the Netherlands.
There is another option which travels via Lille and from Lille direct to Belguim (although you need to swap trains from the French regional line to the Belguim regional line just across the boarder).
The SNCF website will let you know the cheapest option at the time you want to go.
Booking to Brussels first can give you a chance to explore Brussels on the way if you want - there are regular (inexpensive) trains running between Brussels and Ghent all the time. The Paris <-> Brussels leg is the more expensive and (slightly) less frequent one. Often for Thalys, first class is the same price (or cheaper) than second class. The upgrade is worth it.
Approximate Distance from Paris: 280km/175mi
Time to get there: 2 hours - 2.5 hours
Transport Method: TGV from Paris Gare du Nord (change in Brussels or Lille)
Approximate Price: Fares from 51.40 Euro.
Worth: 1 day, potentially overnight.
Website: http://www.visitgent.be/ (available in English)