I am Paris at the moment and for all first time travellers, don't think you need to automatically buy a metro daily card at the cost of 10 euros 55. Because the majority of the sights are within walking distance, i suggest you buy a carnet of 10 tickets at the cost of 13 euros 30. These are not time stamped and can be used throughout a whole stay for zones 1-3. I bought a daily card the first day and only used it twice had i bought single tickets the cost would have been 3 euros 40..
For people whose French is either rusty or non existent don't worry the ticket machines have buttons to press for most European languages. And you can pay for the tickets with a card, just make sure you have 10 tickets when you walk away from the machine.