Hi Sabrina!
I only just saw your post and it was 10 days ago so I hope you see that someone answered you.
I live in France but I am not from England and only taught for a very short time in the UK so I can't help you with comparisons between the two countries with regards to teaching. However, to answer some of your other questions: yes, teachers here do follow a curriculum. Here's a link to it:
ftp://trf.education.gouv.fr/pub/edut...s8_anglais.pdf You need to be able to understand French to read part of it though.
How long will you be teaching these children? Knowing the answer to that will help in suggesting how to go about it. If you have to teach basic English, then teaching them greetings and how to introduce themselves is always a good option. A food theme is interesting and you can have a lot of fun with it. Teaching colours or numbers is useful too and great for basic English. You can extend it to teaching them how to say how old they are as well. Language teaching in France can tend to be rather formal in schools so make sure to have fun with the children by playing language games, singing songs, using stories and by using flashcards.
You can teach a theme around a story or a song which is very useful. You can begin with games and activities to pre-teach vocabulary and language points before you read the story or teach the song and use follow-up games to reinforce what they have learnt afterwards.
If you need any more in-depth information, let me know.