The first definite mention of him in the scientific record is as a friend of an amateur astronomer by the name of Father Pierre. Father Pierre was Professor of rhetoric at the Collège de Lisieux in Paris and as such he was a colleague of Jean Picard and de La Hire. Picard needed help with carrying out calculations for his work Connaissances des temps and looked for an assistant.
Father Pierre recommended his friend Le Fèvre to Picard as a possible assistant and, after Picard had tested Le Fèvre's abilities, he employed him to assist in the production of Connaissances des temps. Le Fèvre thus became an associate of Picard and de La Hire, and these two recommended him for membership of the Académie des Sciences shortly after this. Indeed Le Fèvre was elected to membership and began work with Picard on calculating astronomical tables.
In October 1682 Jean Picard died. Le Fèvre continued with the task he had been set of calculating the tables, and he published Connaissances des temps during the period 1685 to 1701. There is some evidence that in fact he may have published an earlier edition during 1682 to 1684 but this is not certain. He also appears to have assisted de La Hire with the surveys of France that he was carrying out.
Le Fèvre accused La Hire of stealing his astronomical tables after La Hire published Tabulae astronomicae in 1687. This was a strange episode for one might have expected Le Fèvre to be well disposed towards La Hire. Despite the ill-feeling which now grew up between these two men, nothing dramatic happened during the years from 1687 to 1700. Then in that year La Hire's son, Gabriel-Philippe de La Hire who had been commissioned by the Académie des Sciences to draw up new astronomical tables, published in Paris Ephemerides ad annum 1701.
With this publication by Gabriel-Philippe de La Hire, Le Fèvre's anger exploded. It is likely that he felt that he should have been named the official publisher of ephemerides by the Académie des Sciences and he was angry that this commission had been given to Gabriel-Philippe de La Hire when he felt that this he should have been given to him. In 1701 Le Fèvre vented his anger by publishing a preface to Connaissances des temps which attacked both de La Hire and his son. The preface was replaced on government orders by one which praised both de La Hire and his son. Le Fèvre was excluded from the Academy soon after this, almost certainly because of his preface, but the official reason given was his failure to attend regularly meetings of the Académie des Sciences (which was indeed a rule of the Academy).
Le Fèvre continued to publish ephemerides under the pseudonym J de Beaulieu, these appearing in 1702, 1703, and 1706. Lalande identifies J de Beaulieu as Charles Desforges, but McKeon in  argues convincingly that J de Beaulieu was Le Fèvre's pseudonym.
Article by: J J O'Connor and E F Robertson