In the UK:
ATC control air and ground.
AFIS control ground (but the CAA can bust you if you don’t make the right radio call when inbound).
A/G control … not sure 
they are subordinate to the landowner but that is a civil matter and not an ANO matter i.e. a criminal offence. And the CAA can also bust you if you don’t make the right radio call when inbound.
FISO in UK do act like ground ATC but they can’t give tower clearances (e.g. land, takeoff, departures, circuit…), I think AFIS role is not that standardized across countries
AFIS control ground
I’m pretty sure that is incorrect (though a lot seem to assume it to be correct).
An AFIS can issue instructions on the ground which must be followed (assuming not dangerous) but they can’t issue a clearance.
The differences being that you can announce that you are taxing to the fuel pumps. They can ignore that, acknowledge that, or issue an instruction such as going in a specific direction, hold position etc. But they can’t clear you to taxi.
They can instruct you to do/no do/report something, but you don’t need their permission(clearance) to do something that doesn’t conflict with a previous instruction.
This stuff is very country dependent – example.
I think a key distinction is between a criminal matter (breach of the ANO; this is what the CAA is a guardian of) and a civil matter (on the ground, ATC, AFIS and A/G act on behalf of the landowner, in addition to the ANO).
I think A/G are acting only on behalf of the landowner. If they cannot issue a clearance then you cannot possibly commit a criminal offence – other than the more distant idea of endangering an aircraft.
I wonder if @tumbleweed knows more.
In that case he is even more likely to be able to say
Surely the clue is in the title "information service ". Such a person would not be qualified (necessarily) to give a “control service” and under ICAO, which EASA mirror where possible a FISO can only give information and advise under certain circumstances. They can request that you follow a particular course of action and a pilot would be ill advised not to comply, however a pilot can take a different course of action, in the interests of safety, providing s/he informs the FISO that s/he is doing so. In France in calling for taxi ATC might “authorize” you to a holding point whereas a FISO would “approuve” you to taxi to the holding point you have requested. A/G you simply announce that you are taxying to a holding point.
However in recent years, as we all know, the use of the word “clearance” is limited now to certain phases of flight and as the word “authorisée” translates to “clearance” the use of the word “authorisée” is also now in limited use.
Ibra wrote:
I mean you did get clerance to enter or depart CAS but failed to make the call that you have left the CAS
In that case you risk activating SAR.
Ibra wrote:
FISO in UK do act like ground ATC but they can’t give tower clearances (e.g. land, takeoff, departures, circuit…), I think AFIS role is not that standardized across countries
Not at all… In Sweden, an AFISO controls vehicle traffic but not ground aircraft traffic.
I understand that EASA is working on standardising AFIS regulations.
My understanding, UK AFIS control ground vehicles, issue taxi instructions to aircraft and also issue flying clearances to aircraft on behalf of other ATC
The few aberrations, they can “slow down things on ground” and as of now can they can put “ATZ flying on standby”, these comes handy when managing few IFR departure/inbound 
