Laudator Temporis Acti

I don't see Salvian of Marseille mentioned in the index of Benjamin Isaac, The Invention of Racism in Classical Antiquity (Princeton: Princeton University Press, 2004; rpt. 2006), although his book covers a wide chronological range, "from the fifth century B.C. till late antiquity" (p. 2). The seventh book of Salvian's On the Governance of God is full of condemnations of Africans. I've selected just a few examples below.

7.13.57 (tr. Jeremiah F. O'Sullivan):

But in almost all Africans, insofar as it pertains to both, that is, being equally good and evil, there is no balance, because almost the whole population is evil. After the purity of their original nature has been cut off, vice has created in them, as it were, another nature.

in Afris vero paene omnibus nihil horum est, quod ad utrumque pertineat, id est bonum aeque ac malum, quia totum admodum malum. adeo exclusa naturae originalis sinceritate aliam quodammodo in his naturam vitia fecerunt.

7.15.63-64:

As all dirt flows into the bilge in the bowels of a ship, so vices flowed into the African way of life, as if from the whole world. I know of no baseness which did not abound there. Even though pagans and wild peoples have their own special vices, yet, all their crimes do not merit reproach.

The Gothic nation is lying, but chaste. The Alani are unchaste, but they lie less. The Franks lie, but they are generous. The Saxons are savage in cruelty, but admirable in chastity. In short, all peoples have their own particular bad habits, just as they have certain good habits. Among almost all Africans, I know not what is not evil. If they are to be accused of inhumanity, they are inhuman; if of drunkenness, they are drunkards; if of forgery, they are the greatest of forgerers; if of deceit, they are the most deceitful; if of cupidity, they are the most greedy; if of treachery, they are the most treacherous.

nam sicut in sentinam profundae navis conluviones omnium sordium, sic in mores eorum quasi ex omni mundo vitia fluxerunt. nullam enim improbitatem scio quae illic non redundaverit; cum utique etiam paganae ac ferae gentes etsi habeant specialiter mala propria, non sint tamen in his omnia exsecratione digna.

Gothorum gens perfida, sed pudica est; Alanorum impudica, sed minus perfida; Franci mendaces, sed hospitales; Saxones crudelitate efferi, sed castitate mirandi. omnes denique gentes habent, sicut peculiaria mala, ita etiam quaedam bona. in Afris paene omnibus nescio quid non malum. si accusanda est inhumanitas, inhumani sunt; si ebrietas, ebriosi; si falsitas, fallacissimi; si dolus, fraudulentissimi; si cupiditas, cupidissimi; si perfidia, perfidissimi.

7.18.80:

Who could believe or even hear that men converted to feminine bearing not only their habits and nature, but even their looks, walk, dress, and everything that is proper to the sex or appearance of a man? Therefore, everything was put contrariwise, so that, since nothing should be more shameful to men than if they seem to have something feminine about them, in Carthage nothing seemed worse to certain men than to have something masculine about them.

quis credere aut etiam audire possit, convertisse in muliebrem tolerantiam viros non usum suum tantum atque naturam, sed etiam vultum, incessum, habitum, et totum penitus quicquid aut in sexu est aut in usu viri: adeo versa in diversum omnia erant, ut cum viris nihil magis pudori esse oporteat, quam si muliebre aliquid in se habere videantur , illic nihil viris quibusdam turpius videretur, quam si in aliquo viri viderentur.

Somewhat milder is the anonymous Expositio Totius Mundi et Gentium 17.61 Rougé p. 202 (tr. Jesse Earle Woodman):

Africa itself is very great, good, and rich, but the men which it produces are not worthy of their native land. While the land is great and good, its men are definitely not. They are said to be extremely treacherous, saying one thing and doing another. it is difficult to find a good man among them, although it is possible that there are a few good ones among their large numbers.

ipsa autem regio Africae est valde maxima et bona et dives, homines autem habens non dignos patriae; regio enim multa et bona, homines vero non sic. dolosi enim quam plurime omnes esse dicuntur, alia quidem dicentes, alia autem facientes. difficile autem inter eos invenitur bonus; tamen in multis pauci boni esse possunt.