Depending on your travel plans, you can save some money while exploring the whimsical city of Paris by trying this hack when using public transit.

The Paris Metro, the city's subway system ... meaning you do not have to buy two different tickets if you switch from one line to another –– as long as you don't exit the underground system.

One-day Mobilis passes are available for 7.30 euros (about $8.14) for travel within Zones 1 and 2 (most of Paris' top attractions are located in Zone 1). You can buy tickets in metro stations and ...