Not very new (February 2017), Roudoudou has written a multi platform Z80 assembler for Amstrad CPC. It was originally designed for the release of his CRTC³ Amstrad CPC+ demo (cartridge mode, banking, ...).

The last version of RASM is v0.67 (21th December 2017) : bugfix buffer overflow with long filenames for export, export breakpoint in snapshot (unofficial Winape chunk), new directive BREAKPOINT, labels begining with BRK or @BRK for local labels will be exported as breakpoints in the snapshots.