Teachers in France tend to use complex reading materials as supplements for instruction. The present study explores the relationship between such materials, teachers' instructional choices, and students' reading comprehension, focusing on disadvantaged schools. We combined detailed analyses of two books taught to first grade students with classroom observations and assessments of students' comprehension. Although the two books appear simple, they include a number of aspects that complicate their comprehension by children. The teacher dedicated a lot of instructional time to the books and used a wide variety of approaches, including prediction and comprehension discussions, to support children's understanding of the texts. Nevertheless, many students failed to understand important aspects of the stories. Analyses of oral interactions revealed how activities such as prediction led to misunderstandings, and why these misunderstandings persisted in many students' minds. Prediction and comprehension discussions are recommended techniques that are used by many teachers. However, our study shows that these techniques can be counter-productive when they are used with complex reading materials with disadvantaged students and when teaching practices engender metacognitive confusion. Our findings challenge the use of complex reading materials with disadvantaged classes, and question the consequences of doing so in terms of educational equity.