In 1986, he followed up with a study covering early homosexuality in Europe, under the title of L'homosexualité initiatique dans l'Europe ancienne (Payot 1986), which has yet to be translated into English.

[3] The book Les Indo-Européens - Histoire, langues, mythes is a general introduction to the Indo-European language family.

1: De Mycènes aux Tragique, Sergent examines the employment of the Dumézilian tripartite system in Greek epic, lyric and dramatic poetry.

In volume 1, Le livre de héros (Payot 1999 ISBN 2-228-89257-2), the Irish hero Cuchulainn is compared with the Greek heroes Achilleus, Bellerophon and Melanthius and the Irish epic Táin Bó Cúailnge with the Greek Iliad, which, according to Sergent, presuppose an Indo-European "pre-Iliad".

In volume 2, Le livre des dieux, Sergent argues that the Celtic and Greek pantheons derive from a common Indo-European inheritance.