Louw and Fotuali'i, both playing for Bath, appeared at a Premiership disciplinary hearing.
They are free to play again on Tuesday, March 7.
The Bath pair were cited for separate incidences that occurred during the Premiership match against Harlequins last Saturday, February 18.
Louw was charged with tip tackling Charlie Mulchrone of Harlequins, contrary to law 10.4(j) or dangerous tackling, contrary to law 10.4(e) in the alternative.
He pleaded not guilty to both charges and was found guilty of dangerous tackling.
The incident occurred in the first half of the match.
Fotuali'i was charged with punching or striking Dave Ward of Harlequins and making contact with the head, contrary to law 10.4(a) to which he pleaded guilty.
The incident occurred in the second half of the match.
The disciplinary panel comprised of Daniel White (chairman), John Doubleday and David Lidbury.
In reference to Louw's charge, the disciplinary panel said: "The panel found this was a dangerous tackle which merited a low-end entry point of two weeks.
"The panel could not reduce the sanction further in light of the fact the player denied any act of foul play had been committed."
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