tldr: Easy French sentences from classics here.
Years ago I was tinkering with creating my beginner comic book in French, and then researching what made things easy to read in French for those with English speaking background. I learnt that the two main aspects that characterise text difficulty are grammar and vocabulary, with other aspects usually having a much smaller role to play. Through my own research, inspired by my own frustration and anecdotal experience, I learnt that for French the typical readability measures that use word length or even how common a word is for vocabulary difficulty just don’t work for people with English speaking backgrounds. This is because so many of the longer “difficult” words in French are identical to those in English, or close enough not to matter. My experiment demonstrated that you may as well just use sentence length to decide on difficulty, being the simplest measure of grammatical complexity. Despite this, vocabulary matters. It’s just that the words that are difficult are differently distributed than for languages that don’t have this peculiar French-English relationship.
In another of my experiments, I tried to filter a large collection of French text to find extracts that are easy for English speakers. While the extracts that are very easy are not long, they do exist. It’s a matter of playing around with the constraints to get something sizeable. It should also be noted that the text I used consists of French classics, which can be challenging to read. Anyway, it’s been a while since I looked at this. The other day I created a page on this site that contains all the sentences and extracts I found that restrict themselves to the vocabulary and grammar of Episode 1 of my comic book, (le, la, les, de, du, des, et, est, se, que, and present tense third person singular of -er verbs) plus cognates and names. I hope it is useful. More to come.