This chapter presents and discusses the results of a large-scale pilot study carried out in the context of a task-based, blended-learning Business English programme in the Foreign Languages and International Trade department of a French University . It seeks to explore the effects of pre-task planned Focus on Form (FonF) on accuracy in students' written production. Using an action-research framework, the study consisted in introducing FonF pre-task activities in the programme and in analysing written productions of students with a B1 level. The researchers compared the results of the students who completed the form-focussed pre-tasks and those who did not complete these activities. The results show no significant differences in the productions of the control and experimental groups, leading the researchers to question the pertinence of pre-task FonF for B1 learners rather than post-task FonF, which can better cater for individual needs. [For the complete book, "New Developments in ESP Teaching and Learning Research," see ED578581.]