The Australian government links to a 2018 Dutch study for a standards comparison. Although this study doesn't cover the 5G band, the EU-Australia similarities in the 3G-4G band (right columns) suggest the claim of large differences in the 5G band is probably unreasonable in general (but see end of answer for exceptions). Australia is the 1st below the row break in the table below (above the break are EU countries.)
Table 1 Reference levels or exposure limits for the general public for electromagnetic fields in inhabited areas in member states of the European Union and selected industrial nations outside the European Union (situation July 2017)
(There's a page-full of footnotes for that table, which I'm omitting here.)
The "equivalent plain wave power density" e.g. in the 2100Mhz band (3G-4G) is is roughly the same at 10 W/m^2 is most of the countries in that table, although some e.g. Bulgaria or Italy do have a much lower limit (0.1 W/m^2). But these [mostly] aren't the countries highlighted in the questionable poster, except for Italy, and the footnote for Italy says:
EMF from fixed systems for telecommunication and radio or TV broadcasting near homes and their outdoor annexes, in schools and playgrounds, in places with stay greater than 4 hours; elsewhere 20 V/m, 0.06 μT, 1 W/m^2.
So it depends how long the emitter is on in Italy; for stays < 4h it's 1 W/m2.
The number for Russia [0.1 W/m^2] seems correct in the poster as well, assuming it's the 2100Mhz band... but not much else... France is 10 W/m^2 in the Dutch study (not 0.1 W/m^2 as in the poster), China is 0.4 W/m^2 in the Dutch study not 0.06 W/m^2 [poster] etc.
There are loads of documents on 5G on the EU sites (Parliament, Commission etc.), mostly dealing with rollout schedules, but I can't find a 5G radiation limits comparison table between EU countries, so I think those standards haven't been finalized at national levels to allow such a comparison.
The 1999/519/EC directive sets limits up to 300Ghz, so those apply to the 5G spectrum unless EU countries decide to set stricter national standards.
The "basic restriction" in the EU is 10 W/m^2 up to 300 GHz.
Similarly (e.g.) for China
The Chinese general public exposure PD limit at all RF 30–3,000 MHz is 0.4 W/m2, according to GB 8702-88.
That (2016) [Polish] paper also notes:
There is a difference in the exposure limits among European countries, as there is no legal basis for the European Commission, to establish public exposure limits for base stations. In general, Northern Europe is more aligned with 1999/519/EC, than Southern Europe; there are no clear distinctions between Western and Eastern European countries.
Switzerland (in the base of technical feasibility) and Italy apply up to 0.01 ICNIRP 1998 reference level for PD below 2 GHz. Switzerland uses ICNIRP as the fundamental limit on total exposures, and then adds the Installation Limit Values (ILV) layer; Switzerland also implements precautionary exposure limitations, at places of sensitive use, such as apartment buildings, schools, hospitals, permanent workplaces and children's playgrounds.
Polish exposure limit for the general public, for the RF 300 MHz–300 GHz is 0,1 W/m2. As ICNIRP reference levels above 10 MHz are 2 to 10 W/m2, the Polish levels are 20 to 100 times more restrictive. Polish limits are long standing and influenced by the former Soviet status. In the past, Poland used even more restrictive limits; two zones for exposure limits: temporary presence and permanent presence (such as, including houses); the first zone limit was 0,1 W/m2 and the second was 0,025 W/m2. Since about 1998, this separation disappeared and there is only one limit 0,1 W/m2. Hungary moved from the Soviet to the ICNIRP limits in 2004. Luxembourg reduces ICNIRP level by 20 times; Luxembourg limits are newer.
Some European cities set more restrictive limits. Salzburg assessment value of 1 mW/m2 (0.001 W/m2; equivalent to 0.61 V/m); the Salzburg PD threshold is 4,500 more stringent than ICNIRP 1998 level at 900 MHz and 9,000(!) more at 1,800 MHz. The ‘Salzburg model’ seems not to have been effective under any point of view; it has prevented the development of networks, with no evident health benefit for public health; at the same time, it has not settled down the controversies and probably has not reduced public concern  p. 148. In addition to Salzburg in Austria, Perugia and Novara in Italy limit the field-strength to 3 V/m (7.3 % ICNIRP field-strength and 0.5 % PD) and 1 V/m (2.4 % ICNIRP 1998 field-strength and 0.06 % PD), respectively. These city policies often have no regulatory basis.
So actually there is some basis to claim there are some places in the EU with extremely tight standards, although the poster doesn't seem to have mapped them quite right.
Also note that this last paper conflicts with the Dutch one (1st table) wrt Luxembourg. I don't know which one is right with regard to that country; they agree on Poland and Italy though (although the latter paper doesn't have footnote with time-based exposure for Italy). Also, the Russian standards are probably explained by the "Soviet legacy" as well.
It's not terribly clear (what Switzerland does, precisely. The Dutch paper says:
Switzerland: An Ordinance relating to Non-Ionising Radiation
is in force since 2000. Mandatory exposure limits identical
to the reference levels in the EU recommendation apply in
all areas accessible to the public. A stricter, precautionary
limit for the electric field strength of approximately 10 % of
the reference level in the EU Recommendation applies at so
called places of sensitive use (for example apartments,
schools, children’s playgrounds) near mobile phone
antennae, broadcasting and radar installations. [...]
[and the table footnote 23:] ) Limit at places of sensitive use (buildings in which persons regularly stay for longer periods, playgrounds) for individual
antenna installations; otherwise reference level in 1999/519/EC
applies at all places accessible for the public