Purpose: The aim of this study is to evaluate the influence of explanatory texts characteristics on comprehension performances in children from 2nd to 9th grade. Method: Several metrics have been applied to 40 explanatory texts, accounting for length, complexity and age accuracy. Children were asked to read an age-appropriate text, and answer questions evaluating surface, semantic and inferential dimensions of comprehension. Results: Results revealed that all group age obtained similar performances on surface questions, but younger children performed poorly in semantic and inferential questions in comparison to older ones, suggesting a weaker ability to rely on previous knowledge. Comprehension performances were also modulated by text characteristics. Principal Components Analysis identified metrics accounting for text coherence, namely number of words, word length and word frequency with 75% of variance explained. Multiple Regression Analysis allowed us to identify sentence length and word length as predictors of performances obtained at the surface and inferential questions. Conclusion: this research provides interesting evidence to increase our comprehension of explanatory text comprehension in French language for different grades. The results obtained should also be useful to develop further researches using text characteristics to predict readers' comprehension performances.