"Not all the Socialists in the south of France are millionaires," political candidate Alain Joissans murmured thoughtfully. "But it seems that all the millionaires I know of around here are socialists."

Often affluent and politically moderate despite the Marxists overtones of the R party label, the Socialists of southern France are hugging the middle ground in a country of growing conflict between political extremes.

The Socialists are in a strong position to keep city hall of this ancient university town despite a challenge to their decade-old rule by Joissans and other supporters of President Valery Giscard d'Estaing in Sunday's nationwide municipal runoff elections.

Aix and 64 other French cities of more than 30,000 population in which no list of candidates for city council seats scored an absolute majority in last Sunday's first-round balloting are voting agains this week.

While most attention will be focused on Paris, where gaullist leader Jacques Chirac is running a fiercely anti-Communists campaign against the joint Communist-Socialist ticket, the showing of the region's unconventional Socialists will also be carefully analyzed.

In Aix, their margin of victory depends on the Socialists' recovering the votes that went to Communist Party candidates eliminated in the first round.

While likely, the Communist support for incumbent Mayor Felix Ciccolini and his ticket is not automatic. Ciccolini's refusal to follow the national pattern of socialists and Communists running together on single slates for city council seats has not only demonstrated once again the separate personality of the Midi region, but also created hard feelings on the left. The Communists may abstain in large numbers.

The most important national outcome of last Sunday's balloting, in which the allied Socialist and Communist ticket captured or retained 114 out of France's 221 largest cities, appears to have been the psychological boost it has given the five-year-old alliance.

"The alliance had been shown for the first time to be politically profitable for both parties." A Gaullist politician said unhappily in Paris. "Our hopes that the moderate Socialists would break up the alliance rather than go into national legislative elections with the Communists have been set far back.

President Giscard, elected by less than one percentage point over Socialist Party leader Francois Mitterrand in 1974, has frequently indicated that he sees his governing coalition's best chance of retaining power to be an opening toward the Left that would drawn such moderate Socialists into his camp.

If this Sunday's results confirm the trends of last week, they would appear to reduce the chances of significant splitoffs in Giscard's favor. Even Socialist candidates who refused to run with the Communists may now feel that power is tantalizingly near, and that it passes through the national leftist alliance.

If he could have held his traditional Socialist voters, Mayor Ciccolini would have been reelected on the first ballot last Sunday by allowing the Communists to join his ticket. Ciccolini polled 30 per cent, as did Joissains, and the Communists took a surprisingly strong 24 per cent.

But "The Aixios are not ready to vote for a Socialist ticket with Communists on it, not yet, "Ciccolini said. "It would be a big risk here. Socialism has done well in the South because we don't have the ferocioys battle between the working class and the owners that you have in northern France.

"Many more of our people are in agriculture, rather that mines or factories. We don't have the pressures on us to the same extend to knuckle under the owners and vote for the right."

Asked what it meant to be a socialist mayor here rather than to represent "the Right," Ciccolini replied by giving two examples of changes he had made: he put city funds into building and equipping a local sports center that resembles the YMCA in most American towns, and his office sponsored a free open-air cultural festival last year.

Otherwise, the campaign brochures and speeches of this successful lawyer featured a routine record of city management during a period of economic and population growth. Tradition and the relaxed pace of life in a town long popular with American students for a year abroad or postgraduate study help to soften the conflicts that rage across northern France.

AIX flourished under Good King Rene, one of the 15th Century's most enlightened rulers, who organized popular festivals in his days and worked in his own vineyards. Leafy Elms and richly decorated 18th Century mansions make the town's Cours Mirabeau one of the most pleasant thoroughfares in France.

The town's very attractiveness has helped create a major problem for the Aixois. AIX's populaton has tripled to about 120,000 in the last 15 years as the French have begun to flee the pollution and noise of larger cities.

The population also swelled with the repatriation of white settlers from Algeria. Many settled around here. Predictions that they would add an embittered, far rightist element to local politics have not been borne out. Ciccolini adriotly collected a major share of their votes by a patronage system of jobs and influence that would be the pride of any American machine politician.

"They couldn't go with (Charles) de Gaulle," who rammed independence for Algeria down their throats."So they came toward us. Now the returnees have largely assimilated into local life and follow the local political patterns," Ciccolini said.