Grandjean studied law at the Université libre de Bruxelles, where she graduated in 1933 and joined l'Ordre des avocats (the Belgian Bar Association) on 21 December 1936.

[2] Her house in Walloon Brabant served as a clandestine meeting place for the Resistance couple Antonina Grégoire and her lawyer husband Jean Bastien.

She had compromising papers hidden in her country house destroyed by the lawyer general Adrien van den Branden de Reeth.

Marc Aubrion had the idea for the Front de l'Indépendance to produce a newspaper spoof that mocked the major daily French language paper Le Soir.

[3] Andrée Grandjean obtained 50,000 Belgian francs to cover the printing costs from businessman Alfred Fourcroy, who was also in charge of an escape network for Allied pilots.

She obtained a death sentence for the person who had denounced Jean Hansen, a student member of the Resistance who had been shot by the occupying forces, from the Liège Conseil de guerre.

[1] She was president of the feminist association ASBL Foyer de la Femme - Vrouwen Haard Avondsterre, founded by her mother, Berthe Grandjean, in Ghent.

[2] In 1951, when the Front de l'indépendance was in turmoil, she agreed to join the National Secretariat as part of the compromise team elected at the Xth Congress of the organisation.

[1] In 1970, she retired to Licq-Athérey, a small village commune in Basque Country, with her second husband Max Cosyns who owned a farm there and had spent a lot of time there since 1954.

The Centre des archives communistes de Belgique holds biographical documents relating to Andrée Grandjean in the Jean Fonteyne collection.

[2] The story of faux Soir was adapted into a graphic novel by Denis Lapière, Christian Durieux et Daniel Couvreur, and published by Futuropolis on 26 October 2021, 96 p. ISBN 9782754830775