In Paris, it\u2019s hard to imagine a day without smart cards. Invented in France in 1979, the small plastic cards get their brains from a computer chip that can be programmed to allow consumers to chat on their cell phones, buy baguettes and ride the metro. Equipped with a password, they can be used as security devices at office complexes and military bases.While smart cards have been slow to catch on in North America, Europe built its banking networks using the technology instead of the cheaper magnetic strip cards U.S. banks favor. To convert U.S. banks to smart cards would cost more than $12 billion, according to analysts at Frost & Sullivan. But as security concerns mount, U.S. banks will likely make the switch, says Can Elbi, an Amsterdam-based IT hardware analyst for Credit Suisse First Boston. The following is a look at how smart cards pervade a Parisian\u2019s life, using a fictional character named Isabelle who works as a computer programmer in the modern suburb known as La Defense and lives with her husband, 3-year-old daughter and seven smart card applications.7 a.m. Isabelle wakes up to the ringing of her cell phone, which like all GSM (global system for mobile communication) phones contains a smart card chip. It\u2019s her boss asking her to report to work early. This version of the smart card, known as a Subscriber Identity Module, or SIM card, can be moved into a new phone, allowing the user to keep stored information such as directories and voice dialing commands.7:25 a.m. On her way out the door, Isabelle asks her husband to take their daughter to preschool. Once outside, Isabelle steps into a local boulangerie and pays for a croissant with her Carte Moneo, a so-called stored value card. Moneo lets consumers store up to 100 euros (US$110) on the card. Isabelle has Moneo installed on her regular bank card and regularly "charges up" the card at an ATM.7:40 a.m. Isabelle sails through the metro turnstile with a swipe of her Navigo smart card. (A sensor on the turnstile can read the Navigo pass from a distance of several centimeters).8:15 a.m. Our heroine arrives at work at La Defense. She waves a smart card near the door\u2019s security reader to gain access to her office building.8:30 a.m. Isabelle arrives at her meeting. Her boss says she must visit a client near L\u2019Opera to help with an unexpected software glitch.8:45 a.m. Back on the metro with her Navigo card.9:25 a.m. Isabelle arrives at the offices of Societe Generale, a French bank just next to L\u2019Opera. Before working on the client\u2019s glitch, she needs to check her e-mail. She flips open her laptop, connects to the Internet and inserts a smart chip (which she stores in a USB plug carrier on her key chain) into the USB slot on the computer. She is authenticated by her company\u2019s network.11 a.m. Isabelle has solved the software glitch and says au revoir to the client. She calls her friend Natalie and makes a lunch date at the bistro Chartier. When she pays, the waiter comes to the table with a portable card reader. Isabelle types in her PIN, and the money is automatically transferred from her account to the restaurant\u2019s.2 p.m. Back in the office, Isabelle gets a call on her cell phone. It\u2019s the preschool saying her daughter has a fever, and can she come pick her up now.3:30 p.m. Isabelle takes her daughter to the pediatrician, who diagnoses an ear infection. She takes a prescription for antibiotics to the local pharmacy and pulls out her Carte Vitale, a smart card issued by the state that documents health coverage for her family. 3:45 p.m. On the way back home, Isabelle and her daughter pass a toy store. They duck inside and Isabelle pays a few euros for a coloring book using her Moneo card. 4:10 p.m. Back at home, Isabelle activates her cable television service so that her daughter can watch cartoons. The cable box contains a smart card that lets the cable company regulate Isabelle\u2019s programming remotely.7:30 p.m. Isabelle\u2019s husband calls. He\u2019ll be home late. With her daughter snoozing, Isabelle opens her laptop and logs on to her company\u2019s network using the smart chip. She opens an e-mail from her boss: "System meltdown at Societe Generale. Come to work early tomorrow."