export MY_CHROOT="/mnt/tmp"
debootstrap --arch i386 --variant=minbase sid "$MY_CHROOT" http://ftp.de.debian.org/debian/
mount -t proc /proc "$MY_CHROOT/proc"
mount --rbind /sys "$MY_CHROOT/sys"
mount --rbind /dev "$MY_CHROOT/dev"
chroot "$MY_CHROOT" /bin/bash
unmount it after leaving chroot (exit / CTRL + D)
mount --make-rslave "$MY_CHROOT/sys"
mount --make-rslave "$MY_CHROOT/dev"
umount -R "$MY_CHROOT/sys"
umount -R "$MY_CHROOT/dev"