"Salope" is better translated as "slut" than as "bitch".
Bitch can better be translated as "chienne".
It is the general french word for a promiscuous woman.
It also carries a meaning of being egoistical and disrespectful of others. Like the english word "nasty", "salope" has two meanings : sexual promiscuity and egoistical behavior.
When used for the egoistical behavior caracterization only, it can be correctly translated by "bitch".
"Suce, salope!" -- "Suck, slut!"
"La patrone est une vraie salope" :
The female boss is a real bitch.