Begin by welcoming your audience. "Bonjour (or bonsoir) mesdames et messieurs" will do nicely, as it is the expected French greeting.
Apologize for not speaking French perfectly. Unless you are a bilingual Parisian, it is a good idea to admit up-front that your language skills are not perfect. Your audience will sympathize more with you if you are honest.
Start your speech in French with a topic sentence that indicates you are witty and well-versed in French literature. If you can't think of anything, use a quote from a known French writer, including Sarte, Renard or Voltaire.
Outline what your speech is going to be about in your opening. Let your French audience know where you are going with your speech. It is important to stick to your topic, as the French will expect you to deliver what you promise.
Shy away from humor unless you are practically a native speaker and understand the subtle way the French use double innuendos. Slap-stick American jokes will alienate your audience and leave you looking like a bumpkin.
Pull your speech together in your concluding paragraph. Politely thank your audience for attending, and giving you the courtesy of listening to your speech. Remember that the French stress manners.
End your speech in French with a memorable line that links back to your topic sentence. If you can't think of anything, resort to repeating the quotation you started with, or using another equally as memorable phrase.
Edit your speech in French for common grammatical mistakes. Remember that French has masculine and feminine nouns, so check to make sure you use "le" and "la" are correct.