Even if your translation varies widely from the source, you must credit the article you're working from.

Here's how:

• (a) When you create the new article (in your sandbox), or when you add translated content to an existing article, you'll be asked for an "edit summary." Add the following: Content in this edit is translated from the existing French Wikipedia article at [[:fr:Exact name of French article]]; see its history for attribution.
• (b) Place the template {{translated page}} on your new article's Talk page.

When you add (a) to your edit summary, remember that the :fr: is the code for the language you are studying. If you don't know the language code, look to the URL of the Wikipedia you are translating from. You'll see a two-letter code at the start of the web address. For example: ja.wikipedia.org is "Japanese." So, you'd link to the article using :ja: rather than :fr:, which is the French Wikipedia.