If you are catching a train from Gare de Lyon, or nearby Gare d'Austerlitz across the Seine, and have some time free why not go for a wander? There is plenty to see and do.
Below is an map with suggestions for walks including some places to visit.
Interactive Map
Luggage lockers
At Gare de Lyon, baggage lockers are available every day (including public holidays) from 6:15am to 10pm - Hall 3.
Details of Gare d'Austerlitz lockers are here
For more general luggage info in Paris see https://en.parisinfo.com/practical-paris/left-luggage-services-in-train-stations
Gare de Lyon strolls
Stroll around Gare de Lyon (3K purple)
Leaving the station on the north side, cross Place Henri Frenay, go through the archway and walk along Rue Guillaumot. You will see railway arches in front of you. The railway line has now been replaced by a elevated park - the Coulée Verte René-Dumont. Turn left and there's a staircase up to it on the far side of the road junction between Avenue Daumesnil and Boulevard Diderot.
Wander the length of the line, which used to end at the Bastille but now stops a bit short. Come down the steps and continue along the Rue de Lyon to the Basille marked by the 'Colonne de Juillet'.
Turning back and avoiding the skateboarders, take the steps down to the Bassin de l'Arsenal, which is where the Canal Saint-Martin re-emerges.
Walk along the quay and about 3⁄4 of the way along you have a choice, you can either take the steps up and go back towards the station, or have a low-level peek at the Seine. To take a peek, walk all the way to the end and cross the canal entrance on the little bridge and take the cut through to the quayside.
Otherwise, take the steps back up to the Boulevard de la Bastille, cross the road and then walk down the Rue de Bercy. After about 250m you'll pass a photogenic street on your left which has become big feature on Instagram - the Rue de Crémieux.
Continue back to the station and if there's time, why not get a drink at the opulent Train Bleu? (Or you may prefer to grab a bite, or drink, from an Ecotable at Ground Control, a former postal sorting hall which has been transformed into a cultural space and which gets its name from David Bowie).
Park Bercy and a swim? (2K orange)
This quirky little route takes in a little bit of green space in an otherwise busy (and noisy) bit of town.
Leave the station and go left and continue along Rue de Bercy until you get to the large Parc de Bercy. Enter the park, which occupies the site of a former wine depot, and take a stroll around its three gardens - the 'Romatic Garden' (Jardin Romantique - secret gardens, fishponds and sand dunes), 'Flowerbeds' (Les Parterres - 9 smaller gardens including a rose garden, kitchen garden, vineyard and labyrinth) and 'The Meadow' (La Grande Prarie). You can cross the Seine using the footbridge, 'Passerelle Simone-de-Beauvoir'. This takes you to a series of barges. One of them holds water - the Piscine Josephine Baker. You can have a swim here (remember to pack your swimwear), which is about the closest you'll get to swimming in the Seine.
Cross back over the river via the Pont Bercy, or walk a little further along the quay to the Cité de la Mode et du Design which has strong 1970's crime drama vibes as well as some thoughtful graffiti art.If so, cross over the Pont Charles de Gaulle instead and back to the train station.
Coulée Verte René-Dumont
Port de l'Arsenal
Rue Cremieux
Piscine Josephine Baker
Gare d'Austerlitz strolls
Wander around Gare d'Austerlitz (3K blue)
From the station cross the Boulevard de l'Hôpital - i.e. the big road running past the station and enter the Jardin des Plantes (entrance to the right). This is a nice place for a wander and also contains the National Museum of Natural History and the Menagerie, the second oldest public zoo in the world. Walk to the top of the park which is dominated by the Grande Galerie de l'Évolution. As you leave by the exit to the left of the Galerie, you'll see a white building (or series of buildings) with an Arabic feel. It's the Grand Mosque and the bit closest to you is the restaurant if you're feeling peckish.
If not, walk along Rue Daubenton with the mosque on your right and take the first right onto Rue George Desplas past the entrance to the mosque. At the end of the road, turn left onto Rue Lacépède and then first right onto Rue de Navarre which takes you up to the Roman amphitheatre - Arènes de Lutèce. It's a pleasant spot to sit and nibble a sandwich, but if you are looking for Roman arenas, it probably isn't worth cancelling your trip to Nîmes or Arles.
From the arena you can extend your walk and take in the Pantheon and the Luxembourg gardens, which house the Senate, a mini-statue of liberty and a curious puppet theatre (see below).
Otherwise, go back to the Rue des Arènes and at the end turn right down Rue Linné. This takes you back to the Jardins des Plantes. Walk back through the park to the far corner where you'll find the exit leading to Gare d'Austerlitz.
Extension to the Pantheon and Luxembourg Gardens (4K red)
From the Arènes de Lutèce you can go through a passageway on the far side that leads under adjoining apartments and onto Rue Monge. This is where this side of Paris starts to get a little bit hilly.
Turn left and in about about 60 metres on your right, there's a staircase which leads you along Rue Rollin. Turn left at the end to the little roundabout of Place de la Contrescarpe. Take the first right down Rue Mouffetard and continue onto the Rue Descartes as far as Rue Clovis. Turn left past the Saint-Étienne-du-Mont, containing the relics of Saint Genevieve, the patron saint of Paris, and on to the Pantheon.
Look down the hill from the front of the Pantheon and you'll see a very familiar looking tower. Walk towards it along the Rue Soufflot.
This leads all the way to the Luxembourg Gardens which is now home to the Senate, the Luxembourg Museum, Orangery, a replica Statue of Liberty and a puppet theatre.
When you've had enough, you can either retrace your steps or go back via the route below.
Go down Rue Royer-Collard (opposite the Porte Royer-Collard exit from the gardens) and at the end turn right onto Rue Saints-Jacques. Then turn left onto Rue Pierre et Marie Curie which takes you past the Curie Museum.
Turn left at the end onto Rue d'Ulm, then right along Rue de l'Estrapade before taking the left fork onto Rue Blainville which takes you back to Place de la Contrescarpe. From here take a slight right to go onto Rue Lacépède and follow that road all the way back to the Jardins des Plantes.
Walk back through the park and at the far end is the exit leading to the Gare d'Austerlitz
Jardins des Plantes
Grand Mosque
Arènes de Lutèce
Pantheon