Answer:
I can only write this from the perspective of an American, so I welcome any comments from people more familiar with the French educational system.
In the US Education is more a function of each individual state and is free for students, so it is paid for by tax payers. Therefore we possibly have 50 slightly different systems. They are pretty similar for the most part but have minor differences. That means that way that grades are grouped and when classes begin can vary from county to county.
When classes start depends on the county. In my county elementary schools started at about 7:50, Middle schools at 8:30, and high school started at 9:00, but in other counties the times are reversed.
Schools start at the age of five with kindergarten in most places (although I think that some places do not offer kindergarten) and end in the twelfth grade. So technically many students attend school for thirteen years. The most common groupings seems to be that Elementary school is grades Kindergarten-5, Middle School:6-8, and High School:9-12. Many children also attend prekindergartens and preschools in order to learn skills to ready them for school. Children can attend preschool as young as 3.
Public schools offer free and reduced lunches to children from families who are struggling financially and make below a certain amount. The amount of children on free and reduced school lunches is often how poverty is measured in public schools.
The focus of American Schools is on covering a broad variety of content. This is true all of the way through high school. Usually you can also take electives in an area of your choice regardless of what you want to study in college (if you decide to go to college). The idea is for students to be able to think in a variety of different ways and learn to become creative problems solvers and critical thinkers.
Many schools require fine arts classes for a certain number of years, although you can usually choose which one. In my county you could choose between band, choir, drama, and art.
In high schools students take standardized tests at the end of the year on core subjects (Math, Science, History, Language Arts/English), and sometimes in other parts of the year as well. Students also take midterm and final exams. Schools are starting to change how they test students so that less focus is placed on being able to spit out facts and more is placed on critical thinking and showing that they truly understand the topic.
Questions: American class rooms encourage discussion and students are encouraged to answer in classes even if they are wrong because it is considered to be a learning experience. Many teachers operate by the philosophy that "There are no stupid questions". In school we were also told that you shouldn't be afraid to ask a question because someone else may have the same question. Many teachers give students a participation grade.
Types of work done in class: Worksheets done either in groups or individually are a common form of work, but children in middle and high school are often expected to sit through lectures, complete projects that give students a limited amount of freedom to choose their topic, write book reports, essays, and research papers. I think that I wrote at least three research papers in high school. Usually these papers are pretty short (about 4 pages). I'm told that writing this many papers in high school isn't common in some places though.
Technology: Teachers are encouraged to integrate technology into their lessons. Many schools have smart boards and computers in every classroom. Some counties are moving towards giving every student a laptop or a tablet.
Vision and health screenings are conducted through schools in many areas as well (I don't know if all areas do this). If a students has a change in vision or health change parents are notified.
Extra curricular activities including sports, clubs, and community service are heavily stressed. Many clubs have a community service component to them.
I hope this helps. The question was a little broad, so I tried to cover a broad variety of topics. I apologize if the answer is a little long-I've always found this sort of question fascinating, so it's easy to go a little overboard.