May is Bike Month NYC, according to Transportation Alternatives, so it's a good time to report on a trip up and down the Seine with my wife Alice using the Velib' ("Velo-libre" or "free bike") system. This is the less-than-a-year-old brainchild of the socialist Mayor of Paris, Bertrand Delanoe. Paris has more than 230 miles of well-marked cycling lanes and the Velib' has been a big success with more than 20 million trips as of this month, or 70,000 trips per day. At this pace, by the first anniversary on the day after Bastille Day, July 15, the Velib' will have attracted an amazing 25 million trips.

To add our two more trips to the counter, we first buy a Velib' map, sold at any newsstand. The Google map of Paris below has its green arrow pointed exactly to where we decide to join the Seine from the north.

We decide to start with the bicycle route on the north (right) bank of the Seine headed east, ride this until the Seine-side bicycle path ends (it goes north), then cross over the Seine and take the bicycle path west on the south (left) bank to the Branly Museum.

It goes more or less as planned. We walk to the nearest bike station to where we are staying, a bank of about 20 bikes on rue Bachaumont, between Montorgeuil and Montmartre. Parisians and visitors can pick up and drop off bicycles throughout the city at nearly 1,500 locations with 20,000 bikes - an average of 13 per location or approximately one for every 900 square feet. Half the bikes are available at this station at 10 am and a testing of the tires indicates that the first two are in good shape. None of the bikes has the bicycle seat turned around, a signal to other users to avoid the bike and a signal to JCDecaux staff to please fix it.

To unlock a bike, we must go to the muni-meter at the bike station. Despite the "free bike" name, the bikes are actually not free. You must have a credit card. What is free is that: (1) You can put the bikes back in any bike station and then forget about them - a big plus. (2) The per-hour charge doesn't start until after half an hour.

The muni-meter at the bike station sells a one-day card for 1 euro ($1.50) or a 7-day card for 5 euros ($7.50). (Parisians can also buy an annual card for 29 euros and nearly 200,000 of them have done so.) In addition to the cost of the access card, after the first half-hour a supplement of 1 euro is charged for an additional half-hour, 2 euros for another 30 minutes and 4 euros for every additional half-hour after that. Example: a 29-minute trip is free, a 59-minute trip is 1 euro and an hour and 29-minute ride is 3 euros. Clearly Mayor Delanoe is encouraging frequent and short use of the bikes and is discouraging commuters from parking bikes at their offices and riding them home. The average trip time to my surprise less than 20 minutes. A practical purpose of the Velib' system is to ease congestion. In this respect pricing is very similar to the London or Boston subway systems, which make the visitor pay heavily but give big breaks to commuters to encourage them to leave their cars home. (I have noticed a large increase recently in cyclists in London. I am told there was a significant rise in cycling commutation after the July 2005 subway bombing. Congestion pricing has also unclogged the streets in central London and has made cycling easier.)

One issue is the "Montmartre" problem - people pick up bikes at the top of Montmartre but don't ride them back up the hill. It's as though there were free toboggans and - surprise - people pick them up at the top of the hill and check them in at the bottom. Until this problem is addressed (maybe you get a 5-euro credit if you drop the bike at the top of the hill?), a JCDecaux truck is shlepping the bikes from the bottom of the hill to the top.

We frankly have a little difficulty with the muni-meter as may be seen from the two photos.

It requires not just inserting a credit card but answering a series of questions. It's francophone only and my vocabulary alas does not include some of the words the machine uses. It's not as U.S.-user-friendly as most ATM machines in Europe, which allow one to click next a Union Jack to indicate you would like instructions in English. One-third of Velib' users come from outside of Paris and probably an increasing percentage of them will be foreigners. We are lucky to have with us our Parisian friend Edith, who kindly guides us through the muni-meter operation. We buy a 7-day card.

I expect that when the next edition of the muni-meters are installed they will have an easier system as the potential for use by tourists becomes more evident. It would also be helpful to have a way to rent helmets, which we use when we cycle in the United States. Next time we go to Paris we may bring our own helmets.

Once we have our cards, releasing the bikes is simple. We place the card on a marked spot on the bicycle dock until it flashes green and then we remove the bike by pulling it out of its dock-lock. We repeat the process for bike #2 and we are on our way to "chercher la Seine"!