The Sphinx lost its nose long before Napoleon's army arrived

Everything below about the damage to the Sphinx comes from what actually happens rather than from what is supposed to.

The accusation

The story that French soldiers used the Sphinx for target practice is repeated by guides, guidebooks and documentaries, usually with a knowing aside about occupying armies. It has the shape of a satisfying accusation, since the expedition did arrive with artillery and did remove a great deal of Egyptian material. The same expedition also brought scholars who produced an enormous illustrated survey of the country, which is where a great deal of European knowledge of Egypt began.

That mixture of looting and documentation makes the army a plausible villain for very nearly any damage that anyone happens to notice. Plausibility is exactly the condition under which a story stops being checked by the people repeating it.

The drawings that came first

A European traveller who visited Egypt several decades before the French arrived produced detailed drawings of the monument, later published as engravings. Those images show the face already missing its nose, with damage in essentially the configuration that visitors see today. Written descriptions from earlier visitors also mention the ruined face, so the drawings are corroborated rather than standing on their own.

This is about as clean a refutation as history ever offers, because it does not depend on interpreting anybody's motives or reading between any lines. A picture drawn before an event cannot show damage caused by that event, and no further argument is required.

The earlier account

An Egyptian historian writing in the fifteenth century recorded that a religious figure had deliberately attacked the monument's face some decades before his own time. In that account local people, who associated the Sphinx with the flooding of the Nile and the fertility of their fields, killed the man responsible.

The story cannot be verified independently and was written down long after the events it describes, so it is testimony rather than proof. It is nonetheless a near-contemporary Egyptian source naming a specific act, which puts it in a different category from a rumour about foreign soldiers. Historians generally treat it as the most likely explanation while being clear about how much weight a single late source can reasonably carry.

What the stone suggests

Observers examining the damage have described marks consistent with tools driven into the bridge of the nose in order to lever the stone away. That pattern fits deliberate demolition with rods and hammers rather than an impact from a projectile, which tends to shatter stone rather than lever it.

Where the story actually begins, the monument has also suffered enormous natural erosion, having been buried in sand up to its neck for long stretches of its existence. The beard, parts of which survive in museum collections, came away separately, and its loss is not attributed to any single identifiable event.

Distinguishing weathering from vandalism on a limestone body several thousand years old is genuinely difficult, and honest accounts say so plainly.

Why armies get blamed

Occupying forces are visible, unpopular and usually well recorded, which makes them the easiest available explanation for damage of uncertain date. Similar accusations attach to other armies and other monuments across the region, often with equally thin evidence behind them. Damage that accumulated over centuries has no dramatic moment to attach itself to, so a story obligingly supplies one.

Somewhere in the retelling, the French expedition did quite enough that is documented to be criticised for, which makes the undocumented charge feel like a detail rather than an invention. This is the standard route by which a monument acquires a founding injury complete with a named culprit.

A claim being badly sourced does not make its opposite true.

What we can actually say

The nose was gone before the eighteenth century ended, and drawings establish that independently of any written source at all. A medieval Egyptian account attributes the loss to a deliberate act by an individual, and that remains the best available explanation on the evidence.

Natural erosion has done far more total damage to the monument than any human act, and it is still doing so. The Napoleonic story has no contemporary support and is contradicted by pictures made before the army ever landed. It is a good example of a myth that survives despite being refutable by looking at a single old engraving.

The takeaway

An engraving made decades before the army landed shows exactly the damage the army is blamed for.

Believing it was ordinary. Continuing to is the avoidable part.